Unless you think the work they are doing as grad students is worth less than what they're payed (slave-wages) the balance works out that we are getting more from them than they get from us.
The gains we get from paying for research are hypothetical. Research is an investment. Nobody expects it to turn an immediate profit, or even generate a revenue of any significance -- which is great, because it usually doesn't, and most academic research isn't commercially viable anyway.
When we pay for foreign students to earn advanced degrees, only to kick them out of the country once they've graduated, we're cutting off our nose to spite our face. Why are people having such a difficult time understanding this?
You are more correct than I am :)
Right, I agree with you, and I understand your argument (though I don't agree with it per se) that the return is questionable. I was just asking about your claim of "a huge number of foreign grad students and post-docs are being paid off", especially grads in high-tech industry (which is the focus of the article)