I think it's partly a byproduct of all the conventions they do - some fans (at least many of the ones I've encountered on Twitter) truly do think they know what these guys are like. And they want to defend/protect them at all costs. It's bizarre and disturbing, even for online fandom, which is by its very essence kinda bizarre and disturbing lol.
I've even seen the argument that the actors have no idea how much the fans are being (over)charged for these events and that no one should ever mention it to them because they'd hate that their supporters are being gouged. I just find that incredibly naive. These guys aren't just actors, they're businessmen who are there to make money. I literally saw someone say, "Please don't mention to Misha how much his meet & greet went for. He doesn't like knowing people spend so much to see him." You're trying to protect the feelings of a millionaire who is being paid to meet you? That's nuts to me lol. These guys are making bank off of fans, they aren't just showing up to these things out of the goodness of their hearts. They seem like good guys, but they aren't clueless, defenseless woobies in need of coddling lol.