Okay. So after years of hearing this "brony" stuff mentioned I'm finally going to ask. Maybe it was these pics that did it. What is this? I get that it's grown men being fans of a little girl's cartoon to a really creepy degree. But why?
That's not what it is.
Basically, you know how older people are fully capable of liking "kids" cartoons? But there's less stigma about it if the cartoon is supposedly specifically for boys, like Adventure Time?
Well, Lauren Faust basically set out to make a traditionally "girly" cartoon, but with the notion that such a cartoon doesn't have to be basically, bad. And only appealing to little girls who have no sense of anything so will just watch the bright and pretty colors. She wanted to make a good enjoyable cartoon anyone could like. That was the intent and driving force behind the show.
And then people watched it, and found it to be surprisingly fun and good, and the absurdity of a MLP cartoon actually being good and well written drew a lot more people to check it out, usually out of skepticism. And a lot more fans came to be as a result.
It's nothing complicated. It's literally the creator of the show going, "A cartoon about subject matter traditionally being "girly" doesn't have to be vapid stupid garbage. It can be a just generally good cartoon" and then it was and people who aren't so stuffy and insecure that they can enjoy cartoons still despite their age liked it.
Which also means, every single time someone goes "hurr grown men like a cartoon for little girls" that's objectively false. That's NOT what the cartoon was, it was literally made with the conscious intent for it to be exactly not that.