Wow, that seems sort of wack if true. Steam has all kinds of unhinged shit, including that one RPG-Maker game where the H scenes constantly talking about R-wording children. But a clearly adult looking and acting femboy is too much? That sounds like either something is deeply wrong with Steam's content review system or the creator is not being entirely honest.
I actually do have a hard time believing Steam would be so wildly off base for no reason given the seeming complete lack of quality control -- including selling call of duty titles which can compromise your computer's security by just launching them. I don't know anything about the creator, but I can't help but feel a bit suspicious of them for something.