On the topic of My Little Pony yuri (geeze, it took me 3 tries to type that right. It's not exactly something I type often), I don't think there's anything wrong with it at all. The characters are all adults (at least the main 6). Now if it involves Scootaloo or any of the youngsters then yeah I've got a problem with it, but yuri in general isn't accepted in any of the "reputable" MLP:FiM sites. Equestria Daily might have one or two on there by accident, but they're removed very quickly. If you're not into it, don't go looking for it and chances are you'll never have to see or read it.
Now I will admit I've read a few MLP:FiM shipping stories. Now understand there's a HUGE difference between regular shipping and sex fics (called clop fics in the MLP:FiM world). Regular shipping involves NO sex of any kind, but rather focuses on the feelings and emotions of the characters involved. These were previously called fluff fics because they didn't involve anything serious. Regular shipping stories might involve a kiss or two, but sometimes don't even go that far. But as for the people that want to read the stories that include sex, whatever. It's just not my thing, but that doesn't mean someone else can't enjoy it. Also the writers of regular shipping stories are typically MUCH better authors that those that write sex fics.