It was a big surprise to me. The standard story in all of the papers is that legacy admission is affirmative action for white people. In other words, they let in dolts with low SAT scores merely because they had parents who attended the school. The newspapers say this all the time. But the statistics say something different. The Princeton admissions office apparently has so many legacies that they can pick and choose the most amazing.

They actually did modelling of this during the trial. It was found that removing legacy and affirmative action causes negligible change in the white population.

Which the evidence suggests is at most a small effect compared to genetic intelligence, but of course we have to brush that under the carpet.

What’s genetic intelligence can you explain it to me?

I believe they're referring to the heritability of IQ. I think they're asserting that genetics have a much larger effect than environment on IQ scores. I haven't read any recent research on the subject, so I can't vouch for the accuracy of that assertion.

I meant intelligence (the underlying "g" factor) rather than IQ specifically, but other than that, yes.

Why would we have to brush something like that under the carpet?

A longer way of saying "intelligence," more or less.