Except if international students are in the US, then they're contributing to the US economy and not their home economy. They're buying goods in the US, paying taxes in the US and perhaps most importantly, they're exporting US culture back into their home country if they go back or resulting in positive brain drain to the US if they stay.

Do you not realize how bad of an idea it is to just completely cut all of that off? For benefits that aren't even tangible because universities grow to fit the number of students attending?

Again, it's not based in any sort of rational basis. It's xenophobia.