Principally yes, but I'd disagree on essence.

Say you have a minority that's 1% of the population, and unhindered it would also make up 1% of enrollments.

If you don't allow that minority to enroll, you're increasing the acceptance chance of a majority group member by just over 1%, while decreasing the acceptance chance of the minority member by 100%.

The correct way to describe this is then most definitely discrimination against the minority, and not affirmative action for the majority.