"Could you quote where Wade generalized from US tests to global conclusions?"

I'm not sure what to make of this. Is the only thing that will satisfy you a direct quote from Wade saying, "I think differences in IQ in racial groups in America can be generalised out to population groups from other continents?" Is your point that no scientist is literally saying the exact thing you're saying, not by implication and context, but verbatim?

In that case, no, I can't provide a quote to support that. But given that Wade's central claim is that racial differences are based on evolutionary differences between the "races," that's inescapably a genetic argument as far as I can see. Which then means that the differences aren't specific to the US (indeed, Wade is British) but are about "population groups," "races" in this case, across the world.

Wade identifies 3-5 "races" by misinterpreting research from one of the scientists quoted in the article. Not only is this counter to common knowledge (and common sense) about genetics, it again suggests, if you take him seriously, that the fact that one of the "races" happens to be in America would have no bearing on anything else.

And lastly, from the quote that you shared, what Wade is arguing here is that it "may be dangerous to compare the IQ scores of different 'races'"(there's a specific critique of his ideas on race here - https://www.huffpost.com/entry/a-troublesome-response-ni_b_5419505) when you control for income, health etc. I'm curious, what do you think he's implying here?

To be clear, I'm not calling Wade a racist or a white supremacist or anything of the sort. I'm saying that people do so generalise. Fair point about Wade being a writer and not a scientist, but he's presenting his ideas as if they're supported by scientific research. Again, Murray does the same thing. And while I'm confident that you are personally intelligent enough to nuance the specifics of these points, people like Peyton Gendron aren't. That's why these inaccuracies matter.

Also, just a quick aside: I'm sure this isn't intentional, but phrases like "to avoid any accidental memory lapses" sound incredibly condescending. Similarly, repeatedly talking about the inability of "some readers" to talk about racial issues objectively (while assuring me that you aren't referring to me necessarily) still feels very much directed at me.

After all, I don't see how it's helpful to inform me what other readers might do. And I talk about race and racism quite reguarly without getting emotional. So unless I start sobbing and calling you a white supremacist, can we assume that no further caveats about the potential emotionality of racial topics are required?