I get that. It’s common usage today for “crazy” (and similar words) to mean “I don’t understand what they’re thinking.”
I just don’t particularly like that usage, as it lumps people that the speaker disagrees with along with those people who have real psychiatric problems. This trivializes mental illness to the point where pretty much everyone would be considered “mentally ill” by someone, and it’s also a handy tool for putting people whose viewpoint the speaker doesn’t understand into the category of “they’re fundamentally irrational, therefore I shouldn’t bother making the effort of trying to understand them.”
I’m not saying you’re doing either of these things. I’d just like to try to steer the conversation about the mentally ill towards sympathy and getting better treatment for their illness, and to steer the conversation about the not-mentally-ill towards understanding why otherwise-rational people would do horrible, irrational-seeming things. The term “nut job” really isn’t conducive to either.
