There's over 24000 pictures of pony research and counting.
And that was accomplished in roughly three years, while it took about a decade for the pokemon fandom to do the same!
Well, my guess is that the majority of characters in the show are female, leading to a lot of researchographic experiments.
Plus, from someone who doesn't enjoy pony asses (despite from the avatar), the asses kinda stick out from the structure of the ponies:
Too me, it's pretty noticeable. From the front, side, and back. Probably because of the human's pervy nature.
or it's just meFrom those two theories, the show was kinda asking for it.
/goingintothescienceofponyresearch