What an amusing rhetorical question.
Let's state this another way, then. I find labeling other people's behaviors as "irrational" to be at best, uselessly superficial and intellectually lazy. There's no such thing as uncaused behavior, no such thing as action without reason. Dismissing something as "irrational" marks a cessation of honest inquiry into causes and reasons. At best. From there, failure to inquire creates lack of understanding. At worst? Given people rarely if ever use the word "irrational" as a neutral, descriptive term, it's a recipe for self-righteous arrogance and flat-out intolerance of other ways of thinking. The results of that include things like extermination of the so-called "irrational" (undesirable) ways of thinking or ways of life. Or extermination of those lives themselves.
Yup. Sorry. Not a fan. I understand that people throw around the word "irrational" rather casually and that these kinds of subtexts are not necessarily intended by those using that word as a slur. Nonetheless, I would encourage a little humility and understanding instead of tossing around words like that. One can conduct meaningful examinations of the strengths and shortcomings of all ways of thinking without such terms.