The use of the pronoun he to refer to men and women dates back to the 18th century. The Generic He is easier to pronounce and uses less ink.
They already have an alternative: it.
If you tell me you’re neither m/f, I am linguistically accurate in referring to you as an it. You are giving me no other correct option by omitting yourself from the chromosomal (read: real) categories. Even those intersex (“true hermaphrodites“) you love to bring up still fit in the binary, they happen to be both. 1+1 =/= 3
Languages need no more than three terms: masculine, feminine and neuter or neutral, the Other. These are psychological terms and there can be no logical objection to them. Plenty of European languages (those I’m familiar with) have a specific assignment per word e.g. mela is Italian for apple and it is classed as feminine, hence la mela or the apple. Introducing anything beyond the miscellaneous category of neuter is asking for a squared expansion on already densely packed (here, Romance) languages.
You have enough useless liberal arts graduates in your ranks to calculate the basic impossibility of including your personal pronouns on a linguistic level. They are called personal because you have no right to control the speech of another person. They can tell you that birth sex announced by a doctor is The Sex of a mammal for its entire lifespan (as a scientist or sane, honest person would) or they can respond to your passive-aggressive ‘request’ by telling you to accept their personal pronouns (those they use, because language is for dialogue) or fuck off because you’re incapable of healthy speech with another human being.
While you’re at it, Americans especially, quit appropriating the English language for your subculture.
Normal people do not appreciate grammatically incorrect power-tripping.
You’re not oppressed, you’re unpopular. Grammar-Nazi language policing won’t help that.