That's probably the toughest question yet... Theoretically no... it seems wrong... to be violent towards someone who isn't being violent, even if what they say is abhorrent..
I am only human, and what I express can only be an opinion on this...but I can say that I do understand why someone might feel like committing violence... for instance.. someone spouts how he/she is going to torture a small child or an animal.. I AM going to feel violent.. perhaps I am wrong in that.. perhaps I should better learn to control my self.. but I am honest enough to know I would want to suffocate them with their own socks or strangle them with their own knicker elastic..It's probably wrong... there are probably better ways.. a smarter way would to be calm, record the conversation and then go to the police.. I am not sure I have that self control... right or wrong..
I can tell you too that I HAVE been known to threaten violence to someone who is advocating hurting children, women or animals.. I feel I WOULD commit violence... if needed...like if someone hurts my daughter I WOULD do whatever it takes to make them suffer.. I would happily go to jail if someone killed her.. Fortunately for me in my nearly 53 years of life so far I have never had to hit anyone.. usually my anger is enough ..
So definitely... one can use violent words to someone who is expressing totally vile things.. that too may not be right or smart.. but it's not actually using violence :P
I think everyone should a right to free speech and peaceful protests even if I disagree, but when violence erupts then that's a problem. Unfortunately, there's always some maniac who goes ballistic.
I have to say yes to your question as you asked it but IRL I wouldn't be consistent about this question.
Both my dad and my husband had problems with bullies when they were kids and they will both tell you that the only thing that worked for them was beating up the bully after school. Punching a bully in the face is basically suppressing incredibly incendiary speech with violence but if someone punches a bully I would just think they had it coming.
I'm not consistent with this because in other circumstances I wouldn't think it was a good thing to suppress speech with violence.
First of all I should let you know that I am an atheist and what I am about to say involves a religious group but I do not say this because they believe in a god, I say it because scum like this would most likely turn me violent should they turn up at a funeral of one of my relatives or friends. There again if they did it would show that my relative or friend had done the right thing if it upset these despicable sub humans.