Arguably it's a form of brain drain. The US imports a lot of graduate students who got a subsidized undergrad for cheap (or free!) at public universities in their home country.

I should know, I was one of them, and now I'm working and paying taxes in the US. Arguably a net loss to my home country :-P

It's always struck me as weird how the prevailing opinion on hacker news is anti-foreign students / workers...