Do Universities have a right to stop students from talking about questions on tests?
From your link:


  Where a government-funded or affiliated entity such as a University attempts to limit the freedom of expression of its students it must carefully consider the students’ Charter right to freedom of expression, and ensure that any limitation is reasonable, justified and compliant with the Charter.


It seems like the difference between punishing people for sharing test questions and punishing them for criticizing professors is that one of these is "reasonable and justified," while the other isn't.