Since the "he" in question is my teacher and he explicitly said he meant mankind as part of the lesson, I kind of think I know what he meant...

(And honestly your assumption that my teacher must be sexist rather bothers me. Why would you assume that? "Religion has been sexist in the past therefore all religious people must still be sexist"? That's... nonsensical. Especially when the person who knows this teacher, ie. myself, went out of their way to say otherwise?)