Originally Posted by Prestidigitweeze
It sounds as if you're missing pdurrant's point: He is the metonymic genderless pronoun that once applied to both sexes (as well as eunuchs and hermaphrodites). The problem with using it is not that "all or most of the people it referred to would be male." The problem is its semantic suggestion that male is normative regardless of which genders and variants are included or how many of each are represented.
I didn't miss anything. I think these two points are closely related. Society used to be much more sex-segregated. When talking about doctors and nurses, people would often use the generic "he" for doctors, but the generic "she" for nurses. It used to be a pretty good assumption that your doctor was a man and your nurse was a woman. That assumption is bolstered by the assumptions of the language makes. It wasn't a change in language that caused more women to become doctors and more men to become nurses, the reduction of sex-segregation barriers made the assumption that your doctor was a man and your nurse a woman increasingly absurd.