It's unfair because the school gets used to the far higher tuition charged for international students, and they don't allow domestic students in. Or they set aside a max % that can be foreign. The schools need the money. But foreign students take the place of domestic students, especially at selective institutions.

unfair to who? charging so much is unfair to the masters students who are paying too much for something worth far less and admitting so many of them is unfair to the other students (especially asians who are not from china) and staff, whose reputation they damage