Hold them to the same rules as the speaker.
A writer named Parker O’Brien has written a great piece at Medium which offers a solution to student mobs who shout down speakers.
Take a look:
Quick Take: Free Speech on College Campuses
Schools have long understood the volatility of controversial speakers and a disquieting response to this behavior has been the imposition of increased security costs on the organizations hosting the speaker. On a certain level it makes sense, if a group’s event requires increased security, then they should pay for it. However, it is not the group’s event that causes the need for increased security, but the protests launched against it. This allows a sort of heckler’s veto for protesters by driving up the cost of hosting certain speakers.
Allow me to propose a very simple solution. Just as schools allow freedom of speech for event speakers, it should also allow the same for protesters, with the same requirements. This means registering the protest with the school, paying required fees for security and cleanup, and designating a reserved space for the protest. If group events cannot choose an auditorium at random and without approval, then why should protesters be allowed this privilege? This policy would create accountability for any escalation by either side and remove the ability for protesting groups to impose financial hardships on their opponents. Until schools treat both sides equally there is little reason to think that we’ve seen the last of the violence as blame can be readily shifted to ‘outside agitators.’