To put it briefly, we're fascinated by it because of the animation and the humor it has within the show. The brony fandom is another world. We have artists, fanfic writers, people that solely enjoy the show, people that do music, people that work for the show, and much much much more. There's also a dark side to it, yeah...but I'm not going to go deeper on it. I know a lot of peeps out there immediately think of bronies as "weird", "nasty" and "inappropriate", but they haven't heard what bronies are really doing to the community around them. They're doing charity work, helping children socialize, and much more. There are cloppers out there because they CHOSE to be fascinated by "art". And that's where most of the judgment comes from.
I literally cringe every time I hear the word "clop" because I find it absolutely horrifying. I'm someone that wants to stay for what I'm originally a fan of: and that's the show itself.