If you look at the original Tumblr entry, she says she feels alienated because so many Bronies only ship girl-on-girl pairings. I can understand that-- I know I wouldn't appreciate it if I was looking up art and fanfics for one of my favorite "dude" shows or movies, and most of it was homoerotic. I know that there's a lot of male slash for "dude" franchises, but it usually doesn't crowd out the rest of the franchise the way the rampant femslash does with MLP (probably because the peripherary female demographic that makes slash is a lot smaller for those franchises than the male demographic for MLP).