Earlier quoted context omitted.
Really? If not genetics then what is it? Just random??
IQ is largely genetic, even if some people claim otherwise. The evidence for this is now overwhelming: even when different ethnic groups grow up in very similar conditions in the same country, the PISA (which correlates r=0.9 with IQ) scores measured vary greatly. For example, among second-generation children in Germany, there are significant differences in PISA scores. Polish children achieve similar or even better…
Don't you see your the mistake in your reasoning there?
Probably that too can be explained by genetics or maybe by a failing education system but the point is: there are very dumb Germans and very smart Turkish people who would still score different on an IQ test in German. Especially after going through the German school system (which of course would never discriminate against children with a different ethnic background /s) and so on. The confounding factors at play here make the whole comparison without accounting for those factors utterly meaningless.