The reason why people hate bronies is simple, they're jealous. Us bronies have proven to ourselves and the world that we don't care what society's gender laws tell us, we go where we please. In other words, we're free spirits unchained from the male chauvinist ways. We're INDIVIDUALS. 
The sad reality is that most people aren't individuals, they're just sheep following their herd. I have many friends like that. Take my friend Randy for example. He's 21, smokes weed (because he thinks its cool), plays only Madden and Call of Duty, and only watches blockbusters like Bayformers and Battle Los Angeles. I try to get him into other things like criterion collection classics and games like Team Fortress 2, but he just denies them. He refuses to watch the criterion films as most of them are "weird" or "foreign", and doesn't like Team Fortress 2 due to the "Saturday Morning Cartoon artstyle". I tried to show him My Little Pony but he just didn't believe I was serious. And I don't feel embarrassed, I just feel bad for him. I mean to be so closed minded even when an adult.
And that's what I think of people here, just a bunch of Randys. They see our admiration for the show with our gifs, avatars, and memes and they just stick up their noses and ignore. But deep down I feel that they wish that they could be unchained enough to admire something that others despise.