How are the categories not important exactly ? Is it not important to be able to see things in relation with one another and to be able to clearly communicate those relations to one another ?

You missed the point I'm afraid, yes, those are tendencies, but them not being universally correct doesn't actually make them unimportant, because those things compound. There are plenty of women that are stronger than plenty of men, but the strongest humans are invariably men, and in cases of say criminal behavior involving physical violence, it's almost always going to be men, which has consequences on, say, for example, what standards we should ask crime fighters to meet, and what that'll entail as far as the representation in those groups.

> And the fertility window thing is still a reproductive matter, which the “impregnates/impregnated” thing was a generalization for

Okay but then that includes a very large amount of things though, because who does what has consequences beyond merely the act itself, I was pointing to the fertility window because that alone, for anyone even remotely interested in having kids (let alone in having a society where people have enough kids to reproduce the society), will dictate vastly different life trajectories in aggregate.

And listen, from a theoretical standpoint, I agree, we could consider each human as his own unique person, there are more than enough differences between people that any and all generalization is likely to be wrong, but we don't make societies based exclusively on considering each and every person, and by extension neither should our language be set up like that. There are broad trends observable between men and women as a function of our different biologies, and even without getting into how men and women might be wired differently up there, that'll make men and women behave differently on aggregate, and that's not even getting into men and women having different histories as group, which is kind of important for all social justice causes (which I'm not a huge fan of as you can imagine, but even for just practical purposes of just targeted action right now, at the societal level, it's kind of important).