No one told the RadFems that not all women menstruate
I bet I, being a woman, can tell him more reasons a woman isn't menstruating than he can - many of which I'll have experienced myself, so yes, actually, we are well aware that not all women menstruate, and shock horror, even those of us who don't menstruate (or aren't menstruating right now) don't mind other women who do, we don't mind people saying that 'women menstruate', because why the hell would we.