Is he a fan of "The Bell Curve" by any chance?
Well, I'm not sure "fan" is the right word, but I value the book "The Bell Curve" yes, and I do acknowledge that IQ is a valid biological concept and that there are statistical differences between races (a race can be defined as a mildly inbred group of people and is defined by their common ancestry. E.g. whites are people with mostly ancestors living in Europe ~40.000 years ago, blacks are people with mostly ancestors living in Africa ~90.000 years ago etc.). Acknowledging biological reality, however, is NOT the same as being a racist. As a liberal I am anti-collectivistic, and therefore obviously anti-racist. I don't judge people by the color of their skin.
My primary reason for studying this topic is because it strongly relates to the differences between right-wing socialists and left-wing socialists. (if you want to caricature it: Nazis vs Commies) Left-wing socialists believe that all humans are equal mentally. IQ is a social construct, they claim, and the mind is infinitely moldable and smartness is learnt. (This is the archetype leftwing position) BUT it is a fact that there are great social differences in the world. Some are rich, some are poor. Since all people are equal in abilities and IQ is a myth then there must be EXTERNAL causes to these observed social differences. And so capitalism is identified as the great culprit. It is capitalism that causes social differences.
Right-wing socialists (Nazis being the extreme version) accept that people are born with different abilities and that there may be biological racial differences. They just don't like it. They want everyone to be equal and hence the deviants will have to go. In Nazi Germany this meant extermination of the disabled and the mentally handicapped. This was an extreme version of social equalization, right-wing style. The more moderate version of this is not to actually kill the disabled or the intelligent, but to try to make the differences between them invisible in society. You're not supposed to see that someone is smarter than someone else, and this is done by redistribution of wealth. Money is taken from the wealthy smart ones and given to the poor not so smart so as to disguise the fact that there are differences. Similarly in school the able students are held back and the slow students are given extra resources so as to exterminate social deviants at an early age. This could be called Nazism with a human face.
Notice that the moderate left socialists and the moderate right socialists pursue the exact same policies but for different reasons. Left-wing socialists also want redistribution of wealth, not to hide the deviants but because they don't believe in the deviants and that differences in wealth is caused by an injustice. Left wing socialists also want to give more resources to the slow students and hold the smart ones back, because they believe that people are smart because they have rich parents that are able to educate their children better, and so being smarter is a sign of a social injustice and that's why the lefties want to exterminate the smart and disabled. The moderate left does not actually kill anyone, but exterminates the deviants from public view by redistribution. The left doesn't believe they are covering up biological differences. The left believes it is undoing an injustice caused by the wicked capitalism.
Now, as a liberal I am interested in biological differences in IQ because if IQ differences are largely biological and hereditary and IQ is at the same time very important in wealth creation then I can PROVE that the Marxist conception of economics is false. Lefties observe social differences and claim that it is CAUSED by capitalism because we're all born equal in ability. But what if that's not true? What if we're born EXTREMELY different in abilities and that these differences in ability tend to reflect themselves in the form of social inequality? What then? Well, if that's true then we should expect to see EXTREME differences in wealth in capitalist societies, but we don't. There are differences, some even quite large, but nowhere near what we would expect if the left's conception of capitalism is correct. (their view is that capitalism AMPLIFIES differences, and generates a positive wealth feedback: the rich get richer and the poor get poorer.) In fact, even if capitalism was entirely NEUTRAL with respect to creating social differences (i.e. zero amplification) then the observed differences in wealth are still too small. So the only scientific conclusion to draw is that capitalism does not amplify social differences, it dampens them. Capitalism is an equalizer. It is dominated by negative wealth feedbacks. What is this negative feedback? Competition. Competition between the able forces them to undercut some of the value their intelligence has provided for them. Competition causes redistribution of wealth from the able to the less able. It causes a race to the middle.