"Because I Say So"

It is an incredibly arrogant and more importantly irrationalistic thing to tell one's child to believe or do something "Because I say so".  When parents make such a statement, either they have a logically correct reason for whatever they want their child to do—i.e., something both true and knowable by strict logical necessity—or they do not.  In the former case, the parent is treating logical necessity as secondary to their own whims or as unimportant in itself.  In the latter case, the parent does not even necessarily put on a facade within themself that there is a valid reason.  They simply want unwavering, unqualified obedience.  In neither instance can they possibly be in the right.

It does not matter what the real reason why they say this reduces down to.  Perhaps their parents said the same to them as a youth and they stupidly never objected or even attempted to assess whether this is rationalistically valid; instead, perhaps they crave exercising what they perceive to be the power to act as they please as long as their child is the recipient, seeking a deluded form of empowerment.  Maybe they believe, on the basis of erroneous assumptions (assumptions are irrational already), that children cannot understand the reasons they would present.  In any case, they are irrational to believe or behave as if they are above the necessary truths of reason, including the logical fact that it is irrational and/or unjust to force personal whims on other people because they are just that: subjective whims without any authority.

Nothing is true by logical necessity (except that they believe in errors) or epistemologically verifiable or morally good or evil because of their approval, personal pride, or spoken demands.  Employers, pastors, scientists, historians, and spouses might act yo the contrary, and some of the same parents might even selectively object when they do it.  Without necessarily using the exact words, these other people can communicate an identical concept: the logically impossible idea that their preferences or beliefs or illusory authority of some kind (as if anything but logic's necessary truths have inherent authority) makes something true, knowable, or morally good.  They might do exactly what some irrationalistic parents do, neglecting or denying reason in favor of a contradictory and arrogant subjectivism, and pretend like there is nothing higher or more foundational than their own erroneous thoughts.

Reason is not a person's thoughts, yet beliefs are rational or irrational based upon their alignment with reason.  Many people are irrational because they conflate subjectivity with objectivity and preference for truth in one way or another.  It is always more difficult to transition from irrationality to rationality because shedding assumptions and looking to abstract necessary truths requires effort, while making assumptions based on persuasion or preference when one is accustomed to it already takes no effort at all.  Thus, the difficulty of coming to rationalism and the ease of remaining a non-rationalist mean that it is always more likely than not that a given stranger will turn out to be a non-rationalist, if only they are given the opportunity to express their worldview.

Parents are not exempt from any of this.  Mothers and fathers who think being a parent makes them right, or gives them the right to act as if they are correct simply by virtue of being older than their children or being their biological creators, are philosophical insects.  Too incompetent to grasp logical necessity and too self-absorbed to have already turned towards reason, they settle for pretending to be more than they are, preying on the irrationality of any children who would believe them or trying to psychologically manipulate them into giving in.  Saying something does not make it true or morally good, and neither does believing it.  The appeal of egoism stops some parents from discovering or consistently recognizing these basic truths.