Think about this in a way an accountable official would think.
Most universities don't know what they will do yet in the fall. If you make an exemption for people who are currently already in the country, what would that solve? It would artificially pick those students over those who happened to travel home for the summer. You can't do that. That would probably make such a rule unlawful. So you have to craft such a "heavy handed" rule in such a way that it doesn't have loop holes that can be exploited. Don't think lawyers didn't review this exemption for weeks.
And my earlier points still stand.
I'm not trying to convince people that this rule is all that good. But understand where it comes from, and don't think it's all because of a particular administration. There is certainly logic to this rule. You may not agree with it, but I might not agree with closed schools either.