It's not an unusual or unreasonable request, particularly with the circumstances of the game. He couldn't get Wasteland 2 funded because publishers wouldn't back something they didn't see as "popular" enough. For the same reasons, while most games made attempt to mimic the most popular genres and entries, they are also aiming at the largest and most profitable demographics. In this case, the straight white adolescent male. A decent metaphor would be the case of the chainmail bikini. Many people would admit that for a long time, the way women have been depicted in games is...stupid, for lack of a better word. It's a toy to dangle over that demographic. While it's not as bad these days, it's still very present and common. It wouldn't be unexpected to hear someone ask "As long as you're making a game that doesn't exist solely to please shareholders, could you not put all the women in ridiculous skimpy outfits?"
That was the impression I got from the OP of that thread. There weren't asking for, and didn't even mention, in-game romance features. Gay characters in games almost always fit the role of either "nonexistent" or "painful, obnoxious stereotype". I'm not a fan of romance in games and tend to avoid it by a wide berth, but you can ask for better representation without having to advocate entire game features revolving around it.
I dont see why its brought up at all. From the games I have played with set characters. I dont know if most are hetro, bi or gay. I just dont see why it should be brought up at all, unless its relevant to the plot. You say games are marketed to hetro, white, males. But I disagree.
Look at Halo, we never found out what MC looked like, we never found out his sixuality. (unless these in books, I havent read those) And it dosent matter what he is, because it would change anything.
Another game, metro 2033. He is white, but again sixuality is never mentioned (closest you can get is you visit a hoker who robs you). It just wasnt needed. I dont think thats marketing to anyone in particular. He could just as easily be gay. The game just dosent mention it, becuase it has nothing to do with killing dark ones.
I just dont see the point of brining the subject up unless relevant.