I agree that the level of homosocialness/gender segregation is probably a large part of the difference between 19th C Iran and The Tale of Genji, though I guess culture is also a big part, in that even places that are similarly homosocial might have different attitudes toward liking women as people.

Honestly I think gender essentialism is just one of those things that happens when heterosexual people write about Straight Culture, since straight culture is built on gender essentialism and they seem to have about half a dozen other things to deconstruct before they can get to that. (And then there is the division between bisexuals who have completely different tastes in men vs women, who thus join in on the "fun", and those who don't.) Some people also legit seem to have a gender difference fetish and thus like gender essentialism. You will be pleased/enraged to know that I left out the essay on gender by the straight woman who felt thrilled in her womanhood when she was unable to open a jar and had to ask someone she perceived as a man to do it instead, capped by a long sentence on how she liked being a woman and thus frail, weak, small, lacking in upper body mass, etc.