The problem here, dear boy, is that you're not acknowledging biological reality at all.
Only this morning I was reading a fascinating piece about the latest research on the orgins of human language in that organ of statist collectivism The Economist.
It mentions in passing that, and I quote, 'One of the lines of evidence which show humanity's African origins is that the farther you get from that continent, the less diverse, genetically speaking are'.
a) first of all, recent findings show that many people have Neanderthal DNA. This partially undercuts the African origins theory, and must be revised with an African origin + blending with other human races. And if Neanderthals weren't a distinct species, but a race, then it is quite possible that the Asians have a component of Homo Erectus in them. But that's a totally different matter. b) even if the genetic variation within the category of Africans is large compared to other races, this only means that it is an older race.
The implication of this is that population of Africa are not a 'mildly inbred group of people', and are only defined by their common ancestry to the same extent the rest of us are.
It implies no such thing. What "mildly inbred" means is simply that there are genes in common for the group that have totally diffused throughout the population. If the diffusion of the genes common to Africans happened long ago then all the variation in Africans since this time will not alter this common set of genes.
As for the IQ/Race thing as a whole, what people forget is that Africa has always been a harsh environment for people living. Such a harsh environment presents persistent cognitive to individuals who wish to survive in it. If, for the sake of argument, we assume that there is indeed a substantial hereditary component in human intelligence, we would have to also admit that in a harsh environment such as that of Africa we would expect natural selection to produce pressures towards enhanced cognitive ability and intelligence among the populations inhabiting that environment.
Ah, but HARSH environments do not necessarily foster intelligence. Eurasia is harsh in its own way: it has winters. This harshness has a special quality to it: it is highly predictable. Winter comes every year and to an animal that has no fur or natural tools this requires a lot of long term planning. That's a kind of environment that could foster intelligence. You MUST have clothes and shelter, else you die. You MUST plan for winter, else you die. Africa is harsh in a different way, namely that it is unpredictable. The climate is more or less always the same. Food spoils easily, the sun destroys buildings etc. At the same time Africa is not harsh in a specific way: it is very rich in fruit and natural growing food.
Oh, and the Bell Curve drew a lot of its material from the journal Mankind Quarterly, which has some very nasty connections with nasty people of the brown-shirted variety.
Real good argument you've got there. It was said by the WRONG people. Can't even consider an argument if it ain't said by left-approved people. No, sirree. The funny thing is that this sort of thinking is eerily reminiscent of another type of people, those who refuse to listen to anyone who has the wrong color of the skin. Racists I believe they are called. Now, it may seem like a complete paradox that a left-winger thinks exactly like a racist, but not to me. I have after all established quite clearly that there is really no significant difference between a socialist and a Nazi. Both think and judge people by what group they belong to.