@Walter Hinteler,
You somehow twisted this around Walter. Your argument is equating violence and disruption with speech. Speech means communicating a message which can include anger, disapproval; but once it becomes violence or disruption, it is no longer speech.
Let's make it clear what is happening.
A group of students with a minority opinion (in this case US Conservatives) invite a speaker with an unpopular point of view. Liberal groups are responding with the following tactics.
1. They publicize the fact that an unpopular speaker is speaking and rile up as much opposition as possible.
2. They put political pressure on the University administrations to block the speaker from speaking. This is done with very public defamation campaigns launched not only at the speaker, but at faculty of the University.
3. They call for, and they take, direct action to prevent speakers from being heard. This includes shouting down the speaker to prevent them from being heard. It includes physically rushing the stage where the speaker is. It includes pulling fire alarms. It also sometimes includes includes violence, pushing and punching.
Universities should make this pretty simple distinction.
Any speech is protected and any speaker has a platform to express her views be they liberal or conservative to any student who wants to listen. Free speech includes people on the other side voicing angry disapproval, or debating, debunking and dismissing.
Any disruption, violence, vandalism used to prevent speech should be banned.
As long as you accept the principle that violence isn't speech and that speech isn't violence then there is no problem with this. Right now in the US, it is the liberal side that is using disruption, threats and at times violence to stifle dissent on University campuses. You don't see many professors being losing their jobs for expressing liberal views.