First I will begin with a simple argument (will work my way upto why the statement is in itself wrong eventually).
We shall see
You lead with the claim - 'IQ tests are in themself false'
I said IQ is
imperfect, yes it is culturally influenced, and not the sole definition of intelligence. That’s a very different claim. A speedometer may be imperfect in strong wind, but it still measures speed. Likewise, IQ tests are not flawless, but they have shown multiple times that they correlate strongly with measurable outcomes, and this part is factual and studied, in the west that is. But I'll get to that in detail later.
Well of course they are, perhaps, the most overrated pop sci garbage tools ever made. Originally made for the purposes of rooting out children who needed special care, and many other issues that make them inadequate to communicate the common sensical notion of intelligence (the more accurate word would be aptitude) that we assume when we talk about intelligence.
That's just outright false. Even critics of IQ, from famous evolutionary biologists such as Stephen Jay Gould to modern sociologists, ALL admit one uncomfortable (for you) fact:
IQ tests consistently predict real-world outcomes. Academic success, job performance, even health and longevity all correlate with IQ scores. If IQ were ‘garbage,’ it would have no predictive validity. Yet it has
very high predictive validity across thousands of studies. That’s why militaries, universities, and companies still use cognitive testing.
In fact, modern psychology still treats general intelligence (g) as one of the most robust constructs ever studied, why lie and claim otherwise?
Why then do you lead with the assertion that a 12 point range is satisfactory to conclude anything. Quite contradictory don't you think? One claim of yours is the invalidity of IQ tests and in another occasion you assume there is this understood trust of IQ tests between us? Sorry, but IQ tests are not trusted in modern day psychology.
‘not trusted in modern psychology.’ Again, that’s simply false. Look at APA reports, textbooks on psychometrics, or military research: IQ remains central why do you cope so hard? Please explain to me? Psychologists debate
interpretation, not whether IQ measures
something real. It’s like debating BMI, it’s not a perfect measure of health (far from it), but nobody claims it measures nothing.
Now to your final point:
"why take a 12-point average difference seriously, if IQ is imperfect?" The answer is quite simple really: imperfection does
not erase recurring patterns. Weather forecasts aren’t perfect, yet we can still predict winter will be colder than summer.
The 12-point gap is statistically significant, cross-validated, and persists across generations and multiple testing instruments. To dismiss it is frankly denial and cope from your end.