Well that's the thing...
Most 'pollers' like that lump anything with two penises into 'gay porn'.
While adult gamers wouldn't necessarily consider futa, male / female trans, or apocalyptic type games that feature some male / male or futanari stuff 'gay', per se; the population at large does, and i feel they get lumped in.
Also, the internet is larger than the game-making world... Take Asian countries where gay lifestyle is significantly more accepted than in western cultures is probably lumped into that statistic as well, yet there aren't many wester Japanese / Chinese linguists, so those games are largely lost to us.
The lack of a large number of gay inspired games and indeed the thread itself, sort of lends to the fact there there aren't anywhere near as many large scale games in this genre.