I can answer this. It happens every time there is a failure of proof that selective colleges are discriminating against Asians in favor of whites. Since it is not really disputed that selective colleges are admitting URMs who would not be admitted but for their race, this is an easier target for those who want to complain about race-based admissions decisions. But it’s really a red herring.
If you read the OCR report on Princeton, it’s obvious that Princeton considered URM status to be a plus factor, but that there was no evidence that being Asian was a negative factor (or that being white was a plus factor, either). That’s because the issue of whether URMs are getting a preference is A DIFFERENT ISSUE from whether Asians are being discriminated against in favor of whites. I have to repeat this point in every conversation we have on this topic.