I don’t know if French still does it that way, but in high school French class we were taught to use il (he) for gender neutral. Basically everyone (English native class) thought it was super sexist. The teacher basically explained it as “languages are all really old so they retain a lot of obsolete ideals.” IMO that’s not really an excuse for keeping those obsolete parts.
I’m from the UK and I was definitely taught to use the genderless he in formal writing, I remember my teacher commenting on how sexist it was.
Also, no idea where you got the idea that the singular they is only a hundred years old, Oxford puts the earliest use of it to the fifteenth century.
I don’t know if French still does it that way, but in high school French class we were taught to use il (he) for gender neutral. Basically everyone (English native class) thought it was super sexist. The teacher basically explained it as “languages are all really old so they retain a lot of obsolete ideals.” IMO that’s not really an excuse for keeping those obsolete parts.