Liberal Bill Maher criticized progressives because the University of California at Berkeley, cancelled a speech by right-wing author Ann Coulter. She was later re-invited. (The Blaze, April 22, 2017 See I can cite conservative news outlets.) He called attempts to stifle speech by progressives as the "liberal version of book burning" on his HBO show Real Time.
Yes, I agree with Maher. Come on my fellow liberals. We believe in the Bill of Rights. You know, The First Amendment which guarantees free speech. And that means tolerating speech we don't agree with. Because it's out of this marketplace of ideas that truth can come out. The First Amendment protects conservatives as well as liberals.
Second, it is wrong for liberals to resort to violence when protesting these right-wingers. We, liberals are better than that. Don't give right-wing conservatives ammunition to attack our ideas based on lawlessness. Think about Gandhi and how he achieved justice through non-violence.