I was giving a talk about Tiananmen Square’s legacy at an Australian university about two years ago when a young Chinese student put up her hand during the question-and-answer session. “Why do we have to look back to this time in history?” she asked. “Why do you think it will be helpful to current and nowadays China, especially our young generation? Do you think it could be harmful to what the Chinese government calls the harmonious society?”

She wasn’t challenging the facts of what had happened on June 4, 1989. She was questioning the value of the knowledge itself. In the years since I wrote about Beijing’s success in erasing the killings of 1989 from collective memory, I’ve often heard Chinese students defending the government’s behavior as necessary. But this argument was different. The student was deftly sidestepping her government’s act of violence against its own people, while internalizing Beijing’s view that social stability trumps everything else. At the end of the talk, a second Chinese student came up to ask whether the very knowledge of June 4 could be dangerous to “our perfect society.”

For the 660,000 Chinese students overseas, stumbling across these hidden episodes in their country’s history for the first time can be extraordinarily discombobulating, as if the axis of the world has suddenly shifted out of whack. For some, such discoveries are so disturbing that it is easier to discount them as Western conspiracies designed to undermine the Communist Party.