That is an extremely strong statement to make without justification. It sounds like a forbidden knowledge-type of argument. Science should decide if there are statistically significant intergroup variations. But right now, that is strictly verboten by the type of arguments you just gave me. This strikes me as an echo of the resistance to understanding human evolution, but by a group that considers itself to be rational and scientific. It seems some people literally have taken the notion of universal human equality as a revealed truth in the religious sense. These people are hostile to inquiry into the matter because it would literally upset their entire worldview.