Using insults and calling someone argument fallacies instead of actually pointing out the flaw in their logic shows you have political bias.
1. There exists verifiability in many tests. Here, a method, even if it requires slight adjustment, will consistently give the result of identifying intelligent and unintelligent individuals regardless of region or observer. The image listed all the alleles associated with intelligence that were abundantly present in Europeans. You didn't provide any evidence of other alleles that exist outside of those present in Africa. You said they haven't been mapped means you can't find one to prove me wrong.
2. While the environment is in fact true, we also need to take into consideration customs and inheritance. You nurture and nature both define you. Africans have a ghost hominid admixture. Basically, how Europeans have Neanderthal DNA, similarly, Sub Saharan African have their own admixture. The effect of an environment on communities with different hominid admixtures is not the same. This fact can not be ignored.
3. You talk about lead, but Africans never created huge industries where they could get lead poisoning. They built no sustainable or grand structure even before European came, and not even today, even with a lot of assets left behind more than they already had. The lead poisoning was nothing, even after industrialization, compared to that of other nations like India or the USA. Even Roman had more lead poisoning in the classical era than many African regions have today.