Your argument sounds perfectly reasonable to me. Yet I would advise against reversing stupidity. Just because there is a systematic influence that makes it worse for the opressed people, it does not automatically mean that without that influence all the differences would disappear. Although it is worth trying experimentally.
Agreed, of course. I never claimed that there are no intrinsic group differences - FWIW, I believe that there are, they're just vastly smaller than intrinsic individual differences, and thus should be ignored in nearly all non-statistical circumstances. But group cultural differences are obviously very significant, as are group differences in education, opportunity, and support. We can do a fair bit about those, and we ought to.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.