This is splendid--it should be required reading for any other Medium authors who wish to say something substantive about the decision! It's been quite depressing to see the lack of insight in other articles.
The only thing that I would add is that the court was under no obligation to end affirmative action in admissions; they could very well have ruled that the progress of society-wide integration was going less well than anticipated at the time of Grutter, extended the not-exactly-limit-but-kind-of-suggestion-of-one for an additional decade or so, and told UNC and especially Harvard how they needed to change their policies effective immediately in order to be in compliance. However, given the discrepancy that you talk about between what the law allows for and what universities are trying to do, this likely would have resulted in another lawsuit with very similar facts of the matter in another five years or so.