IQ tests are problematic, and are at best general indicators. And seeing as socio-economic conditions can and do influence IQ scores (see the Flynn Effect), trying to use IQ averages in populations to justify claims "whites are smarter thank blacks" makes IQ tests even more problematic.
Probably the best way to up general IQ scores in a population is to assure children get proper nutrition in infancy and childhood. So the real observation here is that IQ scores are probably measuring other phenomenon other than intelligence, making claims that some ethnic or racial groups are smarter than others pretty iffy at best.
Whatever the factuality of the Bell Curve, the Flynn Effect seems to counter it. Intelligence certainly has a genetic component, but it's probable that you won't really determine just how genetics influences intelligence so long as you have large segments of any given population who lack both academic avenues and basic requirements for academic and cognitive performance like decent food.
But hey, I get it, it's the age of the alt-right, where saying "Blacks are dumber than whites" is now apparently some sort of unassailable dogma, and where a previous generation's debunked or at least heavily questioned claims are brought back and again asserted to be absolute truth.