I don't see an issue, if 99% of the people are straight, and the goal of your character is to put the players in their shoes, then making them straight (if sexuality is in the game for whatever reason) is the right choice. Btw I'm not straight
Your numbers are off. The proportion of straight people is closer to 90% in western countries, and this is likely an overestimate as other sexual orientations are still stigmatized in most countries (source).
As a straight guy, I think I can relate better to a gay woman in an RPG than a straight woman. Romancing men is something that knocks me out of the thing still, more than anything else about playing a woman.
That said, about most games IDGAF. It's not like straight men would not play Tomb Raider because the main protagonist is a woman. And even some RPGs, if the female voice actor is better, or the story makes better sense with a female lead, then that's that.
God forbid any game doesn't cater exclusively to the greatest size group. Why not have representation in games proportional to the real life people that play them? If all you care about is plurality, then every character should be straight, Han Chinese men. We should cater to the maximum amount of people, right?
It's not party catering. Or art. It's a money business that has to create games that sell, so that the developer can get paid. That is the main goal. If there is room for a message, without alienating buyers, that's also an option.
Anyhow, we have robots, those sell. We have aliens, they sell. We have unidentified that sells. There's elves and orcs, which sell. Bunnies and hedgehogs. Various made-up things. Tons more. They all sell copies. Find a way to make it profitable, and it will happen. It's not about representation. And it never will be. Unless it makes enough money to make more after that.
It's clearly not about diversity. Capitalism isn't about demographics and equal representations.
That lies in demand. Create actual demand, and game developers will follow. They always do.
Yea pretty much, unless the point is to highlight an aspect of culture like setting your game is Egypt and including Egyptian mythology and history, don't alienate the majority of your audience, introduce them to something different