Nothing in the student's question can be construed as offensive -- she asked in a forum why the US hasn't responded to genocide and oppression of the Uyghurs (her brother has been detained since 2017 by the Chinese government).
In response, the Chinese students in the audience jeered, booed, and left the room. Through a representative group, which may or may not actually represent the students: "[w]e left today’s colloquium because we felt that the atmosphere in that room was extremely hostile towards us . . . [a]t that moment, we were not sitting in a classroom; we were crucified in a courtroom for crimes that we did not commit."
If they were asked to personally answer for their nation's genocide, I could see this remark having validity. However, they weren't, but by rudely interjecting into a clear question they made it about them, and facts and morality are not on their government's side. In addition to this being extremely rude decorum, their response shows a loyalist's denial of reality.