So maybe it would be better phrased as, people will act rationally given their own optimization function that I may or may not agree with. There is the concept of Bounded rationality, in that I am going to make rational decisions given the information I have, and how much cognitive resources I am willing to spend on it. I may not make an optimal decision, but I can make one that is good enough.
Also, someone can rationally choose to do something that I don't agree with, because they have very different preferences than I do; and thus would optimize for those.
Even the same person can make very different decisions at different points. When I was younger, I was more likely to drink a lot. My preference was to have a social lubricant, even if that was bad for brain cells and my liver. You could say that it wasn't a rational decision, but I wouldn't have engaged in the behavior if there was zero benefit.
Also, someone can rationally choose to do something that I don't agree with, because they have very different preferences than I do; and thus would optimize for those.
Even the same person can make very different decisions at different points. When I was younger, I was more likely to drink a lot. My preference was to have a social lubricant, even if that was bad for brain cells and my liver. You could say that it wasn't a rational decision, but I wouldn't have engaged in the behavior if there was zero benefit.