the fact that sub-Saharan Africa, not including European colonization, hasn't advanced one inch socially, culturally or technologically in the past several thousand years? No domestication of plants and animals or usage of the wheel, copper smelting, clothing, nothing. Most groups in Africa hadn't even invented stone tips for their spears, they were and, in some cases, still are using burned points. It's fine for people to talk about how stunted the Neanderthals were because of their lack of technological innovation, but such speech is taboo when referring to the Negroid population.