What do you count as American CS grads? A lot of H-1B holders have a degree from an American school. (Edit) If you hold an American CS degree, aren't you an American CS grad?
If you close that pipeline, you'll lose those students, and then you have to find more funding, because international students usually subsidize local students.
If you close that pipeline, you'll lose those students, and then you have to find more funding, because international students usually subsidize local students.