It is not impossible to be wholly rationalistic whether one was to feel intense, constant, multifaceted emotions or one was to feel no emotion at all (a state that bring a kind of inner lifelessness rather than peace). If a non-rationalist was able to will some or all of their emotions away or chemically manipulate their nervous system, silencing the emotions correlating with it (though emotions are nonphysical), they might think that they have done what is needed to ensure they are rational. Just as having emotions does not make someone irrational, the exact opposite is utterly false. It takes only a moment to realize that neither respectively follows from having or not having emotion.
Full or partial emotionlessness is not rationality because a person has to actually do something on a mental level to be rational instead of just passively lack emotion: he or she has to intentionally come to logical axioms, avoid assumptions, and be open to or able to realize other logical truths that follow from one thing or another. Lacking certain emotions or lacking emotions altogether does not mean a person has discovered or cares about the necessary truths of reason, the only intrinsic truths. It only entails that they do not have emotions!
Many non-rationalists do not even try to pretend like they have no emotions at all except perhaps in very specific social contexts, but everything from casual comments to the way that supposedly emotionless robots in fiction are treated suggests that it is not uncommon for irrationalists to think that if only they would only suppress or not experience emotion, they are by default rational. However, though even a deeply irrational person can become perfectly adjusted to rationalistic thinking (which is about aligning with the laws of logic that transcends thought), rationality is never itself passive.
Rationality is not about humans ignoring or purging their emotions, and reason is the only way to even know the truth about emotions to start with. Becoming so-called robots is not what makes a person know and submit to the necessary truths of reason that could not have been any other way. Indeed, artificial intelligence cannot not actually be intelligent (rational) unless it too is both conscious and intentionally grasps the laws of logic directly, avoiding assumptions and recognizing at least some inherent truths about reason simply because they are true.
One must perceive and think to be able to think about reason, but just thinking or the capacity for rationality does not mean someone is rationalistic, with or without emotions of any kind. Someone could feel and welcome deep, persistent emotions and be perfectly rationalistic, even going beyond the recognition of logical axioms and the rejection of assumptions to discover and savor more truths. Someone could either despise emotion or feel little to none of it and believe things because of assumptions, hold to contradictions, and misunderstand or deny the ultimate nature of logical axioms. To despise emotion for ideological reasons is asinine in itself and contrary to reason because experiencing or craving emotion is not at all what it is to believe in emotionalism.