More of them stayed here than left. And if they hadn't stayed, the US wouldn't be where it is today. I'm friends with the children of those that stayed and they're as patriotic as anyone. Their parents are greater successes here than they possibly could've been in China and they know it. They are not just the kids of China's political elite. It would be better for the US to attract those bright students and get them to stay rather than keep them out or drive them out. They would just go elsewhere to get a similar education and then go back to China. Even today, there are over 400,000 European researchers in the US because it's the best place to conduct high level research.
At Pfizer La Jolla where my brother works, over a 1/3 of the researchers are from outside the US. Many are Chinese nationals on their way to becoming US citizens and plenty are kids of Chinese nationals who emigrated here in the 70's. (The largest contingent are Canadians but I'm guessing you don't have a problem with them.) The US has acted as a brain drain on the rest of the world for decades and continues to do so. Good thing too or the US wouldn't have its huge technological lead. If you want to stop immigration, there are two groups that I'd go after before grad students: Muslims and illegals.
A family friend's life and career was stalled because a white fellow co-worker falsely accused him of selling secrets to the Chinese in order to get a promotion both had been considered for. A year long FBI investigation cleared him but his career at Raytheon was finished. He started multi-million dollar semi-conductor fabicration plants in China, Taiwan and the US a few years later. It's this type of BS that is causing a higher percentage of grad students (Chinese included) to go back to their country of origin rather than stay (as the majority used to).
Every country has talent that can improve upon technology. China has a billion people people to draw from and I'm not so myopic as not to give them credit for their inventions, developments or improvements even if they used other's technology. No one country is responsible for all development. The US even used Nazi and Imperial Japan's research after WWII.
You're jumping to conclusions, PA. I actually like Chinese people a lot. I'm married to a wonderful woman who is half-Chinese and we have a lot of Chinese friends, but unlike you, I can't say that I've noticed they are particularly patriotic, to say the least -- unless it's patriotic toward China -- just opportunistic (which, btw, I don't have a problem with). Many of them are thoroughly brainwashed and very touchy about any criticism of that dictatorship. They're here to make a buck and get an education at the best universities in the world and then go back and help their country. I've heard this reasoning from them over and over and over again. And let's not forget, China does require them to return after their education. We should be much more cautious in allowing foreigners to come here to study, imo (incl. Canadians).
So, do you believe, for example, that if someone were secretly in the PLA or even ErBu, and used being a student here as a means of spying, that this fact would be discovered by the typical H1B hiring and screening process at the typical corporation?