Literally every single point is stupid and thoughtless. Humans have been geographically isolated along the lines of modern racial types for almost 100,000 years. The immune system and the genes that code for its components varies from population to population and many human groups like Jews and isolated hunter gatherers have awful immune systems compared to high population density peoples. Africans are literally resistant to malaria and whites are extremely vulnerable to it, the amount if mutations overcome to produce that beneficial adaptation must have been astronomical. The very existence of geniuses and the unlikelihood that anything more than a few rare alleles working in conjunction produce variants of it disproves the idea that you both cannot overcome the differential of negative to positive, as do many many other traits which are polygenic and vary between races. The next absolutely retarded thing he brings up is the idea that there are only 1 or 2 alleles for most identifying phenos like eye color and limb length, but even dumber he says that this is the thought process behind brain morphology, cortical volume, connectivity, and intelligence, the current research is directly oriented toward the hypothesis that its a polygenic trait that’s affected by a great number of alleles all of which vary in frequency between races and which in aggregate give vast advantages and disadvantages. Finally, he basically ignores that iq is strongly correlated with differences in brain structure and connectivity, and then ignores that this too varies strongly between races and aligns with observed differences in intelligence.
Just adding on to how unrigorous and shameful Mitchell’s rebuttal is, the adaptations that lead to technological advance absolutely must be stored in the genome for progress to be made and to explain why people from primitive socities take multiple generations to assimilate and perform well in these socities.