From my understanding, The Bill of Rights of the US Constitution (which includes the right to free speech) is set up to protect us (the people) from the government interfering with our free speech. The First Amendment doesn’t protect you from me, a private citizen, stopping your speech.
The Patriot Guard Riders, as rosewood has stated, are a group of individuals that bring their motorcycles to funerals of fallen soldiers to drown out the protests of the WBC. They even bring dozens and dozens of American flags to visually block the view of the WBC from the service. This, to me, is an example of the best way to deal with hate speech/groups. The government should not be restricting speech, however unpopular and vile as it may be, because that is a slippery slope that I don’t trust politicians to navigate. It is our responsibility, as conscientious citizens, to meet hate speech with more speech. Protest the protestors.
I would never encourage people to be violent or break the law. As long as you are willing to accept the consequences for your actions you should do what you need to do.