Agreed, we may disagree on the content of his speech but he still has the right to say it. Just like anyone from the left has the right to speak against it.
What is not cool is the violent way of disagreeing with his ability to give the speech. To set fires, destroy public property, and beat up on people who disagree with you? If this was a conservative group doing these things to a prominent Black Rights Matter activist trying to give a speech I have no doubt a lot of people would be flipping on this issue.
I don't think it's right on either side...