That's one valid argument, but another might be that they have started letting in too many St. Barack-like Affirmative Action quota-fillers whom they don't dare stigmatize with a racist grade like "F".
It would cause Yale no end of trouble if the class had 60% A's and 40% F's, and protected groups made up the entire 40%.
Yeah, that occurred to me. But, I don't know how you deal with that without penalizing the people that were competitive admissions.