Extra "genders" come out of societies that have very rigid and strict gender roles and were largely a way to oppress men. Usually gay men or eunuchs or other men they just didn't like.

Women, who were also heavily oppressed, hardly ever got the option to opt out of womanhood in these cultures. Almost like these cultures still fucking knew who was male and female and that extra "gender" was never an extra "gender" to begin with and was just a different social class.