I'm sorry mate, we're just going to have to disagree on this one. Do you know for a fact that that there's no scientific evidence for important biological differences between the races, or do you simply assume there isn't? Because I can tell you that there is. It's not hidden knowledge. The studies into racial differences over a wide field of traits are numerous and varied.
I hate to be so blunt, but I find pretty much all of your assertions as to why certain races excel in certain things to be kind of astounding.
Are you really suggesting that if a population of Maoris or Samoans immigrated to Ethiopia their children would become equivalent long distance runners? No, of course they wouldn't. They're not built for it. Ethiopians on the other hand, are. That's just evolution. And that's not to say that no Maori could ever be a champion runner. It all sits on a bell curve. And the bell curve clearly shows us that more black people are born with what it takes to make great basketball players than white people. Yes, some white people will make it to the top, but never as many as there will be black people.
The idea that race is somehow not biological quite frankly baffles me. The people of the Earth evolved over a hundred thousand years in vastly varying climates and under vastly varying circumstances. This created differences in body types, cultures, susceptibility to certain diseases and yes, cognitive ability. And there's nothing wrong with that.
As for women being timid, I was specifically referring to Asian women, and that is culturally evolved, not biological. But that being the case doesn't make the fact that asian women are more timid than non-asian. Again, I'm talking populations, not individuals.
As to your last point, that was my exact sentiment. Namely, people are individuals, they're not their race. Not biologically or even culturally destined to become a stereotype themselves. But at the same time, it's still fine for us as writers to incorporate what are considered stereotypical racial traits into our characters if our goal is honest, authentic characters.