They also needed to pass another 2 IQ tests, one of staying alive in the war and another in finding a way of having sex with a female.

Your point about pre-selection in the army is spot on, but I would bet quite a bit that neither of these tests was strongly correlated with IQ, particularly because blacks were disproportionately assigned to non-combat roles in an army that was still highly segregated.

Also, the report here was for eleven-year-olds. Earlier in the article, it was reported that cultural effects on IQ run out in the mid twenties of age. So they should report on IQ scores from a later age to sort out the nature from nurture.

They also needed to pass another 2 IQ tests, one of staying alive in the war and another in finding a way of having sex with a female.

If we had any doubt about the signalling here, he makes it explicit. The thing here is a way of criticizing Black households without any blow-back on the reporter: he just has to properly denounce Flynn.

Reminds me of the jokey report on pornography: “he kept showing me the disgusting pictures; more and more of them; he kept bringing them out. I had to carefully examine all of them to understand just how disgusting they were.”