I'm not one of those people who think My Little Pony:Friendship is Magic is a bad show. I've watched it with my nieces and it seems harmless enough, though I just don't get the appeal of the show enough to stick around to watch it on a regular basis.
However, some of it's fans creep me out.
Go on any random image board or 'booru site, and you will find some of the most jacked up MLP Rule 34 in existence. There is a fanfiction saga (in bound book format no less) called "Fallout:Equestria" that crosses over MLP with the post apocalyptic Fallout series, which makes me (as a casual Fallout fan) have a WTF look on my face every time I think about it. There are literal sex toys designed after the characters (excuse me while I bow my head over a toilet on that note) and there are some creepy, creepy people who claim to be married to the characters (who are FICTIONAL TECHNICOLOR PONIES I MIGHT ADD).
Don't get me wrong, I'm not naive. I know that everything can be someone's fetish. I've been to the "asshole of the internet" known as 4chan. I have read Encyclopedia Dramatica, and I have seen my share of shock images, so I'm not a n00b to the internet, but I still can't look at some of the creepier segments of the MLP fandom and not wonder what drugs you have to smoke to get off to colorful cartoon ponies.
Honestly, this doesn't bother me personally for the most part, but I can't help but cringe every time I stumble across one of this program's more creepy fans or their work across the internet and wonder why such an innocent enough cartoon has inspired so much weirdness and depravity.
Seriously, it really disturbs me sometimes.