Well, "should" is a value judgment, first.
But suppose, for the sake of argument, that you could show that black people were superior to whites athletically (on average) but inferior intellectually, due to some genetic predisposition based on the little difference between the two. You and I would agree that the two groups still need to be treated as equals in society, but you couldn't deny that there are real differences that affect their ability to perform in various fields (on average). Now, I can't speak for the latter, but black people _do _ appear better than us in athletic fields.
My point was that, although ideologically I agree that all should be treated equally as people regardless of trivial things like skin colour, it does not follow that there are no real differences that make one group better than another in some field or another. We're not the same, and might not be "really equal" in that sense.
I guess what I'm saying is that we should be careful not to project our values onto objective reality.