>>3622679> from completely gay to bisexual
Bisexual isn't a real sexuality. You always prefer one more than the other, and you have to choose anyhow to form a stable partnership. Bisexuality, especially when self-labeled, is just opportunistic people hopping between partners, or other "polyamorous" people who try to make a lifestyle out of infidelity.
In the absence of social stigmas and learned aversion, everyone would be "Bi" and the category would not exist. There's plenty of cultures where homosexual acts were considered normal and no special attention was paid.