I don't think it's bad that they've included homosexual relationships in video games; in fact I think it's good, but saying that they should make an effort to include homosexual primary characters? Yes and no, it depends on the type of game.
It makes absolute sense in a "choice" game to add that in as a main-plot point for people who choose to game that way. So for BioWare games, yes, that's no a brainer to cater to that audience. However, when you start getting into games without "choice" and dedicated narrative, it's important to give your game mass-appeal. If you work homosexuality heavily into the plot in a way that people can't relate to, it will result in a disconnect for immersion.
It's the same reason why in RPGs the "main characters" tend to be younger, male, and white. They're appealing to their key demographics to give gamers "eyes through which they can relate" to view the story. A lot of RPGs have a love story in them which is important to the plot, if the featured love story (which is not the case in BioWare, love stories are all side/optional in BioWare games) was homosexual I bet it would hurt the sales of the game. Due to their interactive nature, Video Games tend to cater towards the majority rather heavily when they try and create immersive stories.
As a minority myself, I understand this, and just realize it's a consequence of capitalism.