>GP also alluded to international students coming to the US to learn and then taking their big brains back home instead of starting a company here.

I'm not sure this is such a big issue. If the research environment is poor in their home country, the VC environment is probably even worse. Also consider every foreign professor teaching in the US right now is essentially a modern Operation Paperclip victory against their homeland. And there are a lot of them. Plus the student is still contributing to American research efforts as a grad student here. It isn't all unilateral effort unilateral benefit. They are advancing their PIs grant effort. They are probably teaching and mentoring.