??? I do not follow you here.
Might be true. Although I suspect anyone coding in CS is, in a real sense, engaging in a labor of love and not expecting a huge profit from the effort. (Maybe I'm wrong? If I am, let me know!)
Oh I disagree! Making a better story/game should always drive decisions when you're developing a story-driven game. I'm not saying this to be contentious, but why do it if you aren't driven to try to make something good or special?
I expect that people (in the larger world of writing, not just CS) write heterosexual protagonists because in large part because that's what they know, and (I would imagine) at first blush, the market for a gay love story may not be as large as one for a heterosexual one. So, yeah, if maxing out market share is your driving concern, then sure, you'd probably want to focus on that angle. And if you're straight, and you don't know anyone who isn't, then trying to write a good story centered on a gay protagonist might also be a bridge too far for you.
CoG seems to sit in a niche where a large chunk of its market segment might actually want a story with a really well-crafted gay character. In fact, they might just buy it just to give it a try, or support someone who at least was making an effort. Don't you think?
In my opinion, the only justification for having a gay protagonist is: I can tell a better story this way. That's also (in my opinion) the only justification for having a heterosexual protagonist, or literally, ANYTHING in a story. If it doesn't make the story better, then don't do it. If it does, then do it.
Note that from my way of thinking: "I am gay and that's my frame of reference for the world, therefore I will be able to make a protagonist that is even more real and empathetic if she is gay and not heterosexual" is a perfectly good reason to do so. Equally valid is, "I'm straight, and that's my frame of reference, and that's why my protagonist is a heterosexual male. Does that make sense?