I see a lot of fallacy fallacy going on here. What
@Doc Savage Fan has posted contains a lot of problems (most transparently false equivalency), but I think a well-constructed argument about the principle underlying his post is desperately needed. Violence is a means to stop a destructive behavior, not an ideology. Our society was constructed on the principle of freedom -- both in individual belief and in the free exercise (e.g. speech) of said belief. That includes beliefs and expression which are detestable. Our counter to detestable ideology is through exercise of our own freedom and not through the violation of theirs.