The SATs and GREs are not state tests. They are run by private companies.
Distinction without difference — in this case.
Besides, cheating private companies — if they are sufficiently omnipresent to be thought part of "the system" (you know, maintained by "The Man" to keep you down) — is part of Americana since, at least, the hippies.
Chinese students in particular can further legitimize their case by the racism of American college Admission Boards, which favour Whites over Asians (and Blacks over Whites). This article, for example, provides a table from this book, which calculates the SAT-points benefit/penalty for different races: if Whites are treated neutrally, being a Black gains you 310 points, while being an Asian penalizes you by 140 (out of 1600)!
Cheating to protect oneself from such mistreatment would seem rather acceptable...