the race gap is definitely a cultural thing, what else could it be?
I used to think the same way - mostly as a act of faith or dogma. But as I get older, learn more about history, the world, and science, I find myself doubting my earlier faith.
On an individual leverl, discrimination remains both stupid and wrong. Men are taller than women in general, but if you need something off the top shelf you don't ask Danny Devito instead of Geena Davis just because Danny Devito is a man.
However for social policy we may have to come to terms with differences. Perhaps the liberals when they insist on affirmative action aren't being racist, they're just being realistic about how unfair advantage is the only way to let some groups succeed. It may be that conservatives are wrong to think that if we treat everyone equally the achievements of racial groups will even out over time. And if equality between groups is necessary for social stability - maybe we have to discriminate.
It's scary to think that racial differences may be significant because of the social questions it raises. But we may have to stop burying our heads and look at the statistics with an open mind.