I’m going to start this off by saying I am bisexual myself.
Having everyone in Dragon Age 2 be player-sexual was a mistake on Bioware’s side, and a bad idea. When you strip out part of a character’s attitude so that they’re more inclined to date the viewpoint character, that’s silly. It’s on par with fanfiction that specifically goes ‘well I’ll make them gay’. If I walked up to you on the street while your holding hands with another girl/boy and said ‘well I think you’re straight’, that’d be rude.
People mad about Cullen or Cassandra are really weird. Those are two straight characters out of what has been confirmed to be either 7 or eight romances total. If you want to date a woman as a female inquisitor, you still have choices. If you want to date a man as a male inquisitor, you still have choices.
The difference being that not literally everyone wants to have sex with you. And you shouldn’t need that.
Cullen has only ever been shown to have interest in women mage wardens. He had no interest in men at any point.
Cassandra, in DA2, admits to having ‘a crush’ on a male hawke, and admits to ‘a bit of hero worship’ on a woman hawke.
Sorry that your headcanon got ruined, but trying to say that bioware is ‘erasing queers’ is literally insulting, seeing as they are one of what, two(?) companies that even acknowledge that non-straight people exist? They aren’t removing any non-straight romances to favor straight people or anything. You are, in fact, overreacting.