Howdy Everypony! It's me, your friendly Freeper Brony, CtBigPat! Freeper since 1998, brony for nine years, attended five BronyCons and numerous brony meetups.
First off, contrary to what you would expect this isn't a gay thing, it's a nerd thing. Introverts, autists and geeks of all sorts. The weird kids who didn't fit in at school. Think Trekkies but more colorful.
As for the show itself, My Little Pony: Friendships is Magic (the fourth generation of the show and the version that created the brony fandom) is a decent, well written cartoon. But more than just entertaining, the show connects on a deep level with nerds. I describe it as Socializing 101 for all of us who missed that class. The central character is a nerd who gets sent to a small town to learn about friendship. In our sex obsessed society we have forgotten about basic friendship.
Politically, while most bronies are younger people (teens, twenties, thirties)a lot of them lean conservative. When you're an outsider without a lot of friends you learn to take care of yourself rather than rely on others. I attended a Trump rally in 2016 with a fellow brony and the Connecticut Brony meetup group does shooting meetups.
My friends and I at an apple picking meetup a few years ago. I'm in the green shirt and cowboy hat.
My previous post on the subject: https://freerepublic.com/focus/chat/3951453/posts?page=74
Almost Converted at Bronycon: Why Grown Men Dress Up As Magical Horses
(Parody) Everything Wrong With BronyCon in 4 Minutes or Less