Mobs suppressing your free speech is never ok. It is a sign of a government that is no longer in power.
It is unclear exactly what these students are worried about ... the details should be provided. Are they discussing the organization of violent resistance for example? Or are they merely worried that simple discussion of government policy will somehow land them in jail. The latter seems ridiculous but it is worth hearing them out in detail.
And somehow in all of this, people on one side are forgetting the numerous attempts at assasination. And the successful assasination of a CEO. Regardless of your political angles, the risk is severaly one sided by any empirical measure right now. To dismiss this is to remove yourself from serious discussion.