It is true that inter-group variability is tiny compared to intra group variability.

However I strongly disagree that it does not matter in practice. In practice people are not randomly assigned rooms to be in. They certainly do not meet other people randomly. The result is group identity becomes ever more strongly associated and tribes form. Stereotypes are developed and so on.

For example; it does not surprise me that tiny eastern European countries have coders working for Google but much larger and closer minority populations do not. EE workers are natively nowhere close to Google HQ and they don't even share a common language and culture. These are high barriers.

That there exist a larger number of people with the hypothetical potential to code for Google (which surely exist because of intra group variability) within that minority American population is not relevant. Those people do not want to code for Google i.e. exchange their labour in this area for money. The eastern european coders from (really) tiny states on the other hand have a strong desire to work in those domains that computer corporations select for in their workers.

Even though there are many differences between a typical coder in the United States and a typical Eastern European coder, their shared 'tribe' of basically being geeks trumps everything else. That ought to be GOOD news for those who want to avoid discrimination based on the superficial differences but somehow it does not seem to be taken as this. That's politics.

Obviously scientists are under social pressure not to examine such visible differences. This is because they are failures at being scientists. I do not say that lightly. These are atrocious failures of omission. If society only receives measurements it looks for, then why bother doing any research at all? We already know the answers! It is certainly cheaper to confirm society's biases, whether we're in Victorian times or in the present. It's like being a fat man avoiding the weighing scales.

I understand your point about the gen.pop taking complex research with many confounding variables and reducing the results to a simplistic and inaccurate story. That worries me as well, not just in cases of racial discrimination, but as a general error. That said I cannot agree it makes no difference for public policy (because of the non-random sorting I mentioned earlier). Public policy ought to be based on reality, if the map does not conform to the territory problems will occur. Any system that produces inaccurate information and then has to depend on the false outputs will constantly be tripping itself up.

As a last point, although gen.pop can do dumb things sometimes, that is no reason to feed them platitudes. They do however have bullshit detectors which go off when what the media describes to them isn't what they see in their realities. They are capable of complex thought and thought evolution over time and I fail to see how deliberately misleading them can lead to a greater good without dysfunction. Frankly I think a decline in economic prosperity has a lot more to do with inter-group dynamics going bad, with propaganda causing it to be worse, but as a second order affect.

I agree that IQ is far from the deciding factor in most individual cases. 3-5 points really isn't that much. You could get that many points by taking a ten minute walk and a shower! The issue though is that just as gravity does not affect you and I on the microscale we are at, with enough mass/size things start happening that really do impact on us. I don't know if you've ever walked from a room with average people to a room with people who are totally into the thing you're into, but the difference is very palatable to me. I much prefer the second room over the first, even if that first room had a slightly higher IQ. Why? Because I can now get something done! In fact we all can. That almost comes as a relief.