Don't know why this is tagged under gay when there's no gay content in sight.
Not sure how this is mean to appeal to me or any other gay men
You are right, this creator made more games with the same problem, and yes this is discrimination.
The fact that two girls make love with a man doesn't mean that they are lesbians, it's like saying that lesbians like dick... basically a straight guy kink that revolves around a stereotype.
This reduces the sex world to a straight males-only world and gives a wrong image of LGBTQ community.