because China denies its students academic freedom. Oh, no, that's not right — it voted for a boycott of Saudi universities and academics, because of Saudi Arabia's second-class treatment of women. Whoops, I got that wrong — it voted for a boycott of Iranian universities and academics, because of Iran's oppressive government.
D'oh! Wrong again. As best I can tell it hasn't voted for a boycott of any of them; it only voted for "a boycott of Israeli universities and academics yesterday, in protest over Israel's treatment of the Palestinians." Of course.
Thanks to Aeon Skoble for the pointer.