Consistency with logic and itself is a requirement for something to be true, or even to be possible. As will be addressed thoroughly, the idea of seven "Noahide Laws" is inconsistent with logic, as it entails that only these seven things are morally mandatory for all people, while a great deal more is required of Jews. In other words, Gentiles supposedly have fewer moral rights, and Jews have more obligations, so this is racist against both major groups. This idea of the Noahide Laws also contradicts the Bible it is supposedly derived from and consistent with. On this delusional rabbinic system, idolatry, blasphemy, murder, sexual immorality, theft, and eating blood are immoral, and establishing courts of justice is obligatory. According to some, this is all Yahweh and the Bible require of Gentiles or on their behalf--as in there are little to no objective parameters on how the courts should function or what is just or unjust, and anything outside the scope of these exact issues is not really a matter of human rights or obligation. How ironic that nowhere does Genesis 9, where God instructs Noah, address any of these seven issues except for prohibiting murder and eating blood in meat and prescribing capital punishment for murder. However, the account of Noah's flood clearly describes the world as full of violence (Genesis 6:5-12), a category far broader than mere murder, a specific act which does not have to be especially violent at all in the sense of being graphic. The first book of the Bible already condemns a range of illicit albeit unspecified violence beyond that strictly entailed by the so-called Noahide Laws before the commands given to Noah about murder!
Throughout the Torah, a host of statements contradict this rabbinic tradition. Deuteronomy 25:13-16 says God hates all who deal dishonestly seemingly in the context of condemning deceptive commerce, for instance. How could lying for gain, if this is true, only be sinful for Israelites or the foreigners living among them (Leviticus 24:22)? The same act is according to Deuteronomy 25 hated by God along with the one who practices it without respect to nationality or race. Also, the act is the same no matter who performs it or is on the receiving end. Lying is not at all idolatry, murder, theft, and so on. Sure, lying in this way would be for the purpose of theft, but a lie on its own would not be theft whatsoever. For another example, wearing the clothing of the opposite gender cannot be sinful for reasons of sexual morality because wearing and not wearing clothing are not sexual things in themselves. But Deuteronomy 22:5 says God hates all men and women who do this. This is not automatically about sexual immorality due to the aforementioned logical truth. So is it not really sinful itself, only for the Israelites? That is not how Deuteronomy puts it and, more importantly, that would be logically invalid. The deed's nature is the same no matter someone's ancestry!
Do those who subscribe to the nonsense of conventional ideas about the Noahide Laws really think executing children for the sins of their parents is just as long as the law of the land permits it (Deuteronomy 24:16)? Would punishing an irrelevant person, though doing otherwise is a logically necessary component of justice if morality really exists at all, be legitimized as long as it is a non-Israelite carrying the execution out? Genesis 9:6 does not say to never kill a relative along with the murderer or to kill or not kill for any other crime, or anything about what methods are permissible or just. There are many other matters. Is not paying one's workers as promptly as Yahweh demands not a sin of oppression, as the Torah simply calls it in itself, if a Gentile living outside of Israel is the one withholding payment (Deuteronomy 24:14-15)? Why would a religious Jew think that there are only seven Noahide moral laws or categories of laws that Gentiles are bound by when Genesis says no such thing and Mosaic Law outright states that things beyond what they stupidly consider the only seven universal moral obligations are sinful for Israelites and Gentiles, as Deuteronomy 18:9-13 does with necromancy, divination, and sorcery? Necromancy and the rest are not the same as idolatry, murder, sexual immorality, and so on. Yet the text says that these are the "detestable" ways of the nations the Israelites were to drive out along with sacrificing sons and daughters in the fire, that "Anyone who does these things is detestable," and that sins like these are why God would "drive out those nations before you."
Is torturing criminals while keeping them alive for as long as possible justice as long as it is not a Jew engaging in this practice, though Deuteronomy 25:3 teaches anything above 40 lashes is unjust and Genesis says all men and women, not just the Israelites who were not around at the time, are made in the divine image? Any deviation from justice is necessarily injustice; either there is no such thing as morality or the same sins deserve punishment and the same punishments deserve to be enacted on all offending Israelites and Gentiles. But according to the moral relativism of certain distortions of Judaism, as long as Gentile communities create courts of justice, justice is whatever they practice or believe it is, given that they are consistent with their own laws. What about the command to not oppress a foreigner (Exodus 22:21)? In this case and that of Exodus 23:9, the text refers to a foreigner, so no one can hide behind the phrasing of a foreigner living among you in other passages. What else would oppression Biblically be other than deviation from the prescriptions of the Torah and that which would have to be immoral by logical extension? A foreigner can only have the right to not be oppressed if they have the same human rights as everyone else.
A consistent religious Jew of the kind repudiated here, like the evangelical Christian who thinks the New Testament's direct commands alone reflect what is obligatory for all people now, would likewise have to think that it is Biblically permissible for a Gentile to take advantage of the disabled (Leviticus 19:14), to force their workers to labor seven days a week (Deuteronomy 5:12-15), and to physically strike their male or female workers or spouses on a whim outside of self-defense without letting them go free (Exodus 21:26-27). For yet another example, since battery is not murder, a Gentile can assault and inflict non-permanent injury on another Gentile and not be obligated to compensate them (Exodus 21:18-19), as long as the local/national court says that a formal apology is the only required punishment. Alternatively, "justice" could be enslaving the offender for 12 years (six years longer than the maximum term of Exodus 21:2 and Deuteronomy 15:12) and taking all of their property for life. It would also be righteous for a Gentile nation to punish people for leaving crops for the poor (Leviticus 19:9-10) rather than demand that all farmers who live around impoverished people not harvest all of their crops as the Biblical God commands. After all, there is nothing in the seven Noahide laws/categories that would necessitate doing this!
Moral nihilism could be true, but moral relativism is logically impossible. The Bible never actually teaches this asinine philosophy as (many) religious Jews and evangelical Christians absolutely endorse. The Law itself says its tenets are universal (Leviticus 18:24-28, 20:22-24, Deuteronomy 4:5-8, 12:29-31, 18:19-13, and so on), in addition to elswhere presenting many things as mandatory or evil with no reference to nationality (like Exodus 21:12-32 or Deuteronomy 24:1-6) and consistently emphasizing the same moral standard for Israelites and foreigners (Leviticus 19:33-34, 24:22, Numbers 15:15-16, etc.). God revealing laws specifically to Israel and not to all people is irrelevant to whether the moral obligations the laws reflect are universal as must be the case if they are actually true--remember that as a rationalist, I do not pretend to know if Judeo-Christianity is true as opposed possibly and probably true. It does not follow that the same things are not morally required or sinful for everyone else, and if something is truly obligatory or evil by nature, it is by logical necessity obligatory or evil independent of race or nationality as it is. Thus, while it would otherwise contradict logic and therefore have to be false on such ethical points, the Torah does not teach moral relativism or that there are only seven obligations for Gentiles.
One ramification of this is connected to how intertwined what some people consider separate moral and ceremonial subcategories within Mosaic Law actually are, as if a ceremonial law could be obligatory without being a moral matter! If a woman and man have sex during the ceremonial uncleanness of her period, they have sinned according to Leviticus 18:19 and 20:18, with each corresponding chapter of Leviticus also reinforcing that this act along with others are evil for all people (again, see Leviticus 18:24-28 and 20:22-24). This alone means the obligations regarding ceremonial uncleanness as related to sex and periods, found in Leviticus 15, are also universal simply by being connected to something else the Torah clearly says is an issue of cleanness and uncleanness and applicable to all people. There are indeed multiple ways to show that various parts of Mosaic Law really are universally obligatory across history and geography according to the literal statements of the Bible and what follows logically the ideas they articulate! It is not just actions like murder, kidnapping, adultery, and so on that all people must avoid.
It is not as if the prophetic writings do not convey the same moral absolutism across time and societies. Zechariah 14:16-19, after the chapter speaks of God being king over the whole world (14:9), and Isaiah 66:22-24 both mention other or all nations keeping the holidays prescribed in the Torah, such as the Festival of Tabernacles. Zechariah makes it plain that God will directly punish other nations that refuse to participate by withholding rain from them. Such holidays are among the things many people would say are only for the Old Testament Jews to uphold! Isaiah 2:1-5 and Micah 4:1-3 separately predict that in the last days, the "law will go out from Zion" as God judges people and nations in their disputes. People can dispute about far more than cases of murder, sexual immorality, and theft! The law in question is obviously the same one God revealed to the Israelites. Outside of the Torah, the religious Jew who believes in the Noahide laws as described in this post also would find verses that contradict their illogical and Biblically heretical relativism.
There is no escape in the New Testament. They probably do not adhere to the rabbinic distortion of Noahide Law, but the evangelical who hypocritically decries moral relativism taking hold in contemporary Western society and says that the Torah laws are not for all people holds to that which the New Testament sharply rejects. Their hypocrisy is only amplified because the Old and New Testament teach universal theonomy. Indeed, over and over, Jesus says that he did not come to abolish the Law and that it has an enduring obligatory nature (Matthew 5:17-19, 23:1-3, Luke 16:16-17), in contrast with the non sequitur, legalistic customs of many Pharisees in his day (Matthew 15:1-20, Mark 7:1-13). His last words in the book of Matthew tell his apostles to teach his philosophy to disciples of all nations (28:18-20), which obviously would on a moral level center on the Torah's laws as expressions of God's righteous nature. Paul says that sin, defined by divine revelation largely in Mosaic Law (Romans 7:7), is universal to Jews and Gentiles (3:9-18, 22-24) and that Mosaic Law is righteous and what all people should keep (3:29-31, 7:12-25).
Outside of Romans, he states that the Law is righteous in itself and for all sinners to conform to (1 Timothy 1:8-11), citing it directly and elaborating upon its unstated yet logical ramifications as objectively binding (as in 1 Corinthians 9:7-12). The author of Acts records him as clearly not teaching that Mosaic Law is set aside because God changed (Acts 23:1-3, 24:14). Furthermore, John teaches that no one can fully, genuinely love God and Christ without doing doing what they command (John 14:15, 1 John 5:2-3), which is only ever holistically summarized in the laws of the Torah. However, logically, the philosophy of the Old Testament can be true independent of the New Testament, but the New Testament depends upon the Old, so any legitimate contradiction would render at least that part of the New Testament false by necessity. They just do not disagree on the sheer universality of Mosaic Law.
Of course, what the Bible says is not even possibly true if it contradicts the necessary truths of logic. Logic is true in itself, and the possibility, necessity, and knowability of all things is foundationally dictated by logic alone. Moral relativism is impossible because something that really is obligatory by nature is obligatory for everyone and vice versa. Punitive torture, for instance, cannot be both just and unjust depending on whether a Jew or Gentile is carrying it out. It does not matter how anyone personally feels, for morality does not exist or have the tenets their conscience would suggest just because they have an intuition, preference, or emotional reaction. The law of the land is not any more philosophically authoritative: it is just an erroneous human construct people look to for illusory validation in their stupidity, too irrationalistic to see that their subjective conscience and conflicting or arbitrary social norms, including all laws of merely human origin, have no veracity. How you feel about an action/intention does not mean it, much less anything else, is good or evil; tradition or approval from lawmakers does not make anything good or evil either. If there is good and evil, nothing should or should not be done based upon one's racial ancestry.
Logic, people. It is very fucking helpful.