I wonder if both things can't be true.

Maybe some of these folks demonizing raiders got reasonable advice at some point in their lives like "please pull wall to wall," "stop using cure 1," or "please don't stand in the telegraphed AoE" and told themselves that raiders are toxic elitists that demand perfection.

Have you seen the general population in PF lately? You can avoid basically all negative interactions by not being the worst player in the group, which is, in practice, a very low bar to get over. The vast, vast, vast majority of player-to-player interactions in raiding are exchanges of silence after a lockout of wiping, then going about separate ways. Nobody judges or cares--nobody says anything at all in fact, except in the most extreme circumstances.