so even if some governmental policy somehow made it easier for black people with an IQ of 90 to succeed than for Jewish people with the same IQ, I would still expect a black physics professor to be smarter than (say) a Jewish truck driver.
That's not the point. The point is that the black physics professor is less smart than the Jewish physics professor.
But the difference is smaller than for the median black person and the median Jewish person. (I said "even just knowing what their job is would screen off much of it", not "all of it".)
Here's the new thread for posting quotes, with the usual rules: