>>7655617No, they are not, most people are heterosexual. The "modern" concept (and by modern I mean that it is ~2000 years old) is monogamy, but that's because monogamy is essential for the stability of society. Since first-world societies are beyond that (or at least believe they are and haven't collapsed yet), people revert back to their animal instincts (monogamy for females, polygamy for males). Being bi for women makes sense because they can only have a baby every 9 months anyway.
Strictly defined sexualities are eroding because people live in cities with millions of people and there's the internet, compared to having just 200 people in your village around you. But when people were living in tribes they weren't any more bi/gay (except for the cultural enforcement). But since you can have a new partner every day and never run out, and that modern life is really comfortable and easy, people are playing around. That plus all of the chemicals that fucks with hormonal systems that have been released everywhere.
I'll add that this is not a judgment in any way, people are free to do whatever they want as long as it's between consenting adults
