Free speech as a Constitutional right has restrictions, like all Constitutional rights.In other words, you do not like free speech. His views should be countered by the views of others, so what are you afraid of? The free and open exchange of ideas is the hallmark of our nation. Please tell us, at what point in your life did you embrace Marxism?
Furthermore, Twitter is a private sector company and is not bound to provide unrestricted free speech to users.