It's true that I'm not gay, but it's incredibly unkind and unfair of you to imply that I don't genuinely care for what's best for the homosexual community for that reason. You know so little about my life and can't possibly imagine the reasons I have to hope for every kind of equality for LGBT folk. There's very little difference between us, after all, and my reasons for hating the player-sexual romance mechanic are that it is, in fact, biased against gay characters. I'm actually arguing in favor of the same thing you are -- a 1:1:1 ratio if we can have it, and bisexuality if not.
But players being able to pretend that their non-preferred sexuality doesn't even exist? No.
Let me try to explain. I can see that your intentions are good, but you're thinking of this issue from the perspective of a socially concerned straight person instead of a gay person. The notion of a few homophobic morons deliberately misinterpreting the character design to have their anti-gay fantasy has not been on the minds of anyone in the gay community that I know, and was certainly not present when DA2 came out. The overwhelming reaction, instead, was "HOLY **** WE ACTUALLY GET TO CHOOSE OUR ROMANCE OPTIONS NOW." Because that's what had been missing from our game experience up until now. Not deliberately defined characters with carefully set sexualities; hell, those had been in many, many other games beforehand, but almost always they were straight. And the mere fact that the universe is opening up now to allow for more choices--especially when they were not, like in DAO, just adventurous promiscuous (or formerly so) rogues--far outweighs anything that some other idiot somewhere might interpret. He's not going to have his mind changed by Dragon Age anyway. And believe me, there are so many other things that I find so much worse that you can do already in DA, like genocide, that ****** me off quite a bit when people brag about them, but there's nothing I can do about that.
If you want to ensure that no one can inflict socially unjust headcanon on their DA universes, let's start out by demanding that everyone side with those who are brutally downtrodden in-universe who frequently echo similar groups IRL, whom many players gleefully kick around.