I have a question about MLP

Ok I have seen the show. I don't get what is so great about it, but what I find even more puzzling is the fact that people hate Bronies so much. I know grown men who are relatively tolerant, not bothered by gay people, guys who like fantasy and animation themselves who go absolutely *beep* about bronies. I am a member of one webgroup that was almost brought down due to the conflict between bronies and their haters.

I have to ask WHY? What is the big deal about bronies?
Is there some good reason for hating them that I just don't see?