Can abstract rationality be extracted from a viewpoint that causality permeates all human actions?

Originally, this query started as: Is it moral to use A.I. to emulate and subvert the art styles of propaganda artists? I'm still interested in this question, but I wanted to keep the original question preserved so that my chain of logic can be followed.

I am asking this question because (in light of recent events) I do not believe that viewing all humans as logical beings is (at least, currently) a rational viewpoint. If one can use artificial intelligence to attempt to utilize the sway of certain artists for a more beneficial purpose, is it moral to do so? Generally speaking, I do believe Kant's reasoning in regards to the killer-at-the-door problem is sound, but I don't actually think the majority of people in my country have the faculties to withstand propaganda. I suppose a more fundamental question would be "are irrational humans considered humans in a meaningful way" or "can I use irrational humans to benefit rational ones" but I find both questions to rely on the question of what rationality is - and my own perspective is that humans are perfectly causal and thus rational in a Darwininan context, so I have difficulty extracting a meaningful definition of rationality from that. Is there anything I could read that would touch on this?