It’s proof of inferior culture, not of inferior genetics.
And you know this how, exactly? I mean look at the 100 Meter Dash at the Olympics - any Olympics since 1970. It's all blacks, be they from Jamacia, USA, or even places like England that have very few blacks. Why is that? Is that culture too? No. Obviously not. Blacks are better at somethings than white are because of their genetics.
Is there anything, any area at all, where Whites might be, generally, better than blacks? Well in fact that question can probably be answered, but a lot of people have religious beliefs that don't permit it to be.