Re: Your "nutter on a rampage" is China's "Tiananmen Square"
But then again, you have to draw a line somewhere because some speech triggers instincts. Thus the US v. Schenck decision (declaring that something like falsely shouting FIRE in a crowded theater amounts to inciting a riot--the mere utterance triggers the preservation instinct and exploits it for ill). But then comes the hard questions: WHO draws the line, and WHERE do you draw it, for this is morbidly like the old pizza-topping puzzle: no one can ever agree.