I think this a "whoever wins, we lose" kind of deal. Except from any kind of fan-fiction standpoint, it's total win.
Okay so: a guy on Deviantart likes erotic drawings of My Little Pony characters. Strange, but not unheard of.
But then he gets the equivalent of a cease and desist letter when another guy who claims he's going to marry Twilight Sparkle - for real, because he's found a chapel that will marry fictional characters and real people - gets upset that when he goes to fan forums, he sees depictions of his "fiancee" in sexual positions with the Deviant artist. He doesn't mind people fantasizing about his bride-to-be, but insists she wouldn't be a submissive. He's particularly upset that anyone would draw Twilight having her face ejaculated on (so are the rest of us, but for very different reasons, I imagine).
To think that in my adolescence I thought there was something seriously wrong with me when I had an erotic dream about Zarana. I feel downright square nowadays.