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
Social security would be able to soak them up (its the largest holder of treasuries). And it'd be helpful for interest rates to go up to slow federal spending.
Is the party somehow disgruntled about this too? The proposed retaliations read like a wish list.