That's called "Lewontin's fallacy", and is incorrect. That is only true when you measure individual alleles. However, genes do no evolve alone, they evolve together, which creates correlations between alleles that are unique to races and ethnic groups. That's how gene testing companies are able to tell you your race and ethnic group. Those correlations and genes are very similar to each other by every measure, and very distant to other racial and ethnic groups. This is all very well understood.