Answering someone's free speech with violence is only throwing gasoline on an already burning fire. It will only cause more problems and escalate the level of antagonism. To answer free speech with violence in a governmental sense, it would depend on such free speech I suppose. If a dude walks around the street cursing at everyone driving by then that is when you arrest him. Even in this case, however, the "violence" is saved to paid pros.
You should respond verbally. If you hit someone, you are only escalating the fight. I don't there is a need to react violently when the attacker keeps it verbal. If someone uses their free speech to you bully or harass you, you should report it so someone, fighting back physically will only lead into a fist fight.