Perhaps Saletan is here founding a new movement (at least a new movement to give an old movement a respectable public face): Rational Racism.

I suspect that what resonates as most existentially aggravating about thinking such as Saletan displays here, to those of us it rubs wrong, lies below the threshold of any reified logic: we intuit a fluidity of existence that category sharpeners like Saletan seek to frustrate.

But to give a more scientifically respectable answer, I'd refer anyone to the problem of inconspicuous multiplicities in correlation making.

Reductionist certainties seem constantly seductive to post-religious thinking.

Yet, there are indeed ways of showing attempts to reify particular empirical correlations to be yet further spurious jumps to metaphysical certainty. Even if one is supposing 'only' the certainty of one present instance. Search for the critiques of the Cartesian mentalism which centers Western science.