>>29253760Women are naturally cooperative. They are more easily influenced by their friends and their sexuality is more fluid. Studies show even straight girls find other women attractive even if they have no inclination to turn that into sex or a relationship.
Male sexuality is more set in stone. There's some mixed research on bi guys that suggest some/many are closeted gays but that could be due to the cultural taboo as you suggest. Neurological studies find that men really are born that way and their sexuality doesn't shift anywhere near as much as women. It makes sense since reproducing for prehistoric men was a much more winner-take-all system, so any circuitry that tells them they don't need to compete as hard would be selected against. Culturally, some men are willing to go for gay sex if there's no available females for a long time, but then immediately lose interest in males when any female shows up.
It makes sense. Male homosexuality does seem to be evolved, probably somehow benefiting their siblings' offspring by noping out of the mating competition entirely, but the male sex drive doesn't serve its purpose if most men can satisfy it without reproducing. But for women, sexual fluidity makes a ton of sense and is more clear. A tribe can survive a shortage of men, but its long term viability rests on its supply of fertile women. In addition to the benefits having a few gay males seems to provide, a degree of sexual interest and fluidity among women can help them secure protection and provision from each other, two can share a highly desirable male with less destructive conflict if they are also somewhat attached, and romantic interest can facilitate accepting a new woman into the tribe (female mobility between tribes is common among primates and reduces inbreeding).