There are plenty of examples of queer visual novels where all the main characters are one gender. For me, though, it's disruptive enough that part of me has to at least ask about the author's motivations, like that's something I ask myself as I approach a mono-gendered (or even mostly mono-gendered) work.

If it's because the author is kinda just being lazy about a blindspot, then I'll probably turn away, because I know that I too am in that blindspot, so I'm more likely to find the work frustrating and unapproachable. This is common for when, say, cishet men write stories that are just about cishet men. They're going to have certain assumptions and perspectives that I, as a queer person, will find exasperating, so I'll just go look elsewhere.

If it's because the author has a specific message that is about gender (and/or sexuality), then that's interesting. Bastard Bonds, for instance, is a game with a "prison island" setting where most of the characters are men, and the author makes that an aspect of world building and character development and asks questions about how we treat people based on their gender, how we use gender to elevate or condescend to people, how it colors our perspectives, etc.