Because the alternstive means they would have to examine if they're "nice guys" too. The ones that holler the loudest already know the answer deep down. That's why you'll find them elsewhere out and out justifying shitty conduct, rather than this kind of gaslighting you've described. You'll see lots of solidarity and sympathy for men who have "been done wrong by evil bitches", but only about specific things and other places mocking men for being vulnerable about their hurt. One wonders about the focus on those comments.