“I do not believe in genetic inferiority.”
And yet, if you watch professional sports, you plainly see that in certain sports such as basketball and football, teams are dominated by certain races that are physically stronger, can run faster and jump higher than white athletes. You say that isn’t genetic? If genetics can favor certain races’ muscles, can’t the same principle be assumed for brains as well?
To your last question, Yes, absolutely. But given a few generations the differences blur significantly. Have you ever read about the ‘hybrid dog and cat’ effect? Mongrels are usually recipients of the strongest genes from both parents. So when blacks and whites mix the races, their ioff-spring tend to be better than merely one or the other race. It shows up significantly in music aptitude.