Yes, they could "possibly" do that, but they aren't, so why the hell is this relevant?
Harvard admitted 2,200 undergrads in 1988. In 2018 it admitted 2,000. It took me 30 seconds of googling to find this.
It is absolutely true that if you do something for group X, you could have done more for group Y instead with the same resources. But saying that doing something for X automatically takes away from group Y is arguing the counterfactual, "Here is what you would have done if you had not done that." But you don't actually know what they would have done. Maybe they would have reduced admissions even more than they actually did. Can you prove otherwise?
That may seem like a rhetorical question, but it is not. Discovery gives access internal communications which could make that case one way or the other. But it is a case that has to actually be made, and isn't simply a foregone conclusion.