To be clear: most people who are keen on making such an argument, or who are identifying racial genetic differences as the primary takeaway of studies like this, are doing so to justify racism, either implicitly or explicitly.
But that's a strawman. Racism is wrong, even if there are minor genetic variances across populations (which... seems obvious?) Variance within a population strongly dominates the weak cross-population effects, and personal history (nutrition, education, etc) strongly dominates that.
And that's setting aside the moral implications of judging someone or changing your behavior towards them even if you have somehow measured them to be "less intelligent," as if that was a single axis of worth.
Because, apparently, this needs to be said.
This interest in IQ has a negative effect on the concept of intelligence, never mind human unity. It attaches exaggerated importance to test scores, jobs, and school. It tends toward snobbery.
I think the discussion in recent years has refocused, embracing ethnonatalist implications and challenging the core assertion that "racism is wrong".
My main resistance to that is much the same as yours: the differences are so small, that re-architecting society around them is not going to be enough juice for the squeeze.
But one could also argue that the juice is not even the point: by re-architecting society in this way, you "pre-brutalize" your population so that their threshold for violence against "others" is lowered. Thus your population is closer to being wholly militarized, and theoretically is more effective in war, and is less captured by "weak" or "unmanly" moral ideals, such as empathy.
While this might seem a virtue to someone of an expansionist mindset, in application this principle never, ever works well - again, thanks to those tiny differences. If a citizen is pre-brutalized to have a lowered resistance to killing those with curly hair, how long is it before they kill their next door neighbor with wavy hair, over something like lawn furniture?
Pre-brutalizing your populace to killing any sapiens is enough to brutalize them towards harming anyone else. This is the core of the "imperial boomerang", or the colonial boomerang theory, as to why the great wars of the 20th century took on such a nasty character. The ease with which we dehumanized subject populations was - all too easily - redirected against the neighbors, most memorably with Germany trying to re-create the American West to their East.
And yet you are also likely to argue “weather is not climate”. Differences in population characteristics of all kinds have massive societal implications and we should lean into addressing them.
> most people who are keen on making such an argument, or who are identifying racial genetic differences as the primary takeaway of studies like this, are doing so to justify racism, either implicitly or explicitly.
That may certainly be true.
(Not OP, but) I always shutter when we want to deny scientific results because it might be "helpful" for someone making a racist argument.
My personal belief is that truth is the goal of science. Even in cases where the truth is uncomfortable.