Although I'm not a fan of My Little Pony, I can still agree that it's a great show. In fact, possibly one of the best shows for kids that is currently on TV.
However, many people (myself included) avoid that show like the plague because of how nasty the fanbase is. Some of the discussions that you can stumble upon with bronies are just... horrifying.
Though, if you're a kid and you like this show, that's good for you. Same thing for adults as well. But sheesh, the fanbase for this show is worse than the Sonic fanbase.
That said, that's probably why people are giving you flak for enjoying this show. I'd say ignore them and enjoy what you enjoy.