It is a dog whistle, the groups they talk about includes race, and based on how such people act it is obviously a paper made to encourage racism. By having published that paper now the racists can motivate their racism by saying "Fairness is impossible, I have to be racist here, just see this paper!", I don't think that such behaviour should be encouraged and I don't want racist dog whistles to get any support.

Otherwise the paper is pointless. Fairness is still possible as long as you disregard unrelated groupings, just look at the individuals relevant traits and evaluate those so fairness isn't impossible at all. Fairness is only impossible if you want some race or group to get a certain number of spots and they wont get those with a fair distribution, in that case you made fairness impossible since you added an extra requirement, but that isn't what most people mean with fairness. The only reason to add that requirement is that you want to treat a specific group unfairly, and the most salient such group are Asians in college.