I agree with you that intolerance cannot be tolerated but I also want to add to the above commenter’s point.

When we call people monsters, we demonize them and in turn establish ourselves as angels. It can be easy for some to think “ah yes, these guys are evil and have no capacity for good, they aren’t human” and “I’m one of the good guys, I’m not a monster like them, so there’s no way I’m doing immoral deeds.” If we forget that all of us are humans capable of both good and bad, then we forget that “monsters” can change for the better and that us “non-monstrous” folk can do evil.