I know who did it, I just don't care.
I mean in theory, I couldn't give a damn less what people want to ****** to in their off hours jahannam is waiting; my biggest beef is adults (in specific, adult men) muscling in on what is supposed to be a safe space for little girls and demanding they have their needs catered to and generally making the fandom an unsafe environment for children. Obviously there's only so much parents and older demographics can do, but I feel like the fact that the hysteria around this show has birthed these weird-ass phenomena means that more effort needs to be put forth when it comes to sparing its intended audience alienation and abuse.
While there is a lot of interaction between the show crew and the fanbase, I wouldn't say that the fanbase has been "muscling in" on it. By and large, the show has not changed much from Season 1 and Season 2, which were largely written and produced long before they became aware of the periphery demographic. There are absolutely some who -are- "like that", but the writers and producers have been pretty steadfast in keeping the show pure, as it were.
As for the fandom itself ... there is very little interaction between the main demographic and primary demographic. You won't find little girls on Equestria Daily, or /mlp/, or at cons. That extends to the merch too, which is mostly Hasbro's end. Sometimes their merch or the stuff they license contains nods to the fandom and its ways, but it too mostly remains the domain of the little girls. There are sites like WeLoveFine, which deals in t-shirts, that are mostly oriented to the adult fanbase and have very little interaction with the little girls, but they are also resolutely safe.
Now, there are the types who post creeper comments on Claire Corlett's YT account and deride the little girls as "not being real fans", but they're a minority and ****** nobody likes them. They're the ones the term "brownie" was coined for.
And as far as the internet goes ... there's not really much you can do about it. There is a campaign where on given days of the month some will take to Google and go through what Images returns for what would be common search terms on Safe Search and flags things that would be considered "naughty", and the tumblr fanbase has been campaigning for greater vigilance about tagging NSFW. So that's some of the things that the fanbase does, and it helps that the cloppers and the seedier bits mostly inhabit the dark corners of the internet.
But you have to be a completely irresponsible parent to let a 4 or 7 or 11 year old go on the Internet without supervision. You can't hold the fanbase responsible for your own failings in that regard, and any moral panic about MLP and things being "unsafe" can be easily applied to just about every children's cartoon on the planet. Rule34 and FF.net are full of smut for Fairly Odd Parents, Jimmy Neutron, Avatar: TLA, the Powerpuff Girls, and all the others. The Internet is not a safe space, and never has been.
EDIT: Also worth nothing that 90% of the porn drawn and written on the Internet is done by women, which holds true in the small horse fandom as well.