"'Death to the Jews,' is that an incitement to action or an idea?"
Neither. It's an opinion, which should not only be allowed, but there should not even be a debate. Also, people seem to forget that, up until recently, it was okay to say that you wanted the death of an entire group of people. What wasn't okay was to single out a specific, identifiable person. Now, the former is becoming the norm, and you can see this actually covered in many online Terms of Service, which is, on its face, ridiculous in the extreme.
"But I don't think anyone is saying that 'hate speech' is just the expression of ideas. It's the expression of ideas that is held to incite criminal and/or illegal behaviour."
I AM SAYING THAT. I am not liable for the thoughts which you have when you see the swastika on my arm, yet that same swastika can get me arrested in some places. Likewise, I am not liable for the thoughts which you have when you hear certain words that I might say. I don't control what goes on inside of your brain when certain auditory or visual impulses hit it.
I AM SERIOUSLY UPSET THAT THERE ARE SO MANY PEOPLE LIKE YOU IN THIS WORLD. You actually believe that the mere conveyance of opinion should be banned because it might cause someone to do something. Think about what kind of world your children and their children will have if this kind of thinking becomes even more pervasive.
The true meaning of life is to continuously evolve towards some end, of which we are presently unaware. Said evolution requires unfettered communication to proceed apace, especially given that "evolution" is now becoming less rampantly biological and more self-directed, such as through technology, particularly nanotechnology. When said communication is censored, in any fashion, evolutionary progress is hampered. Thus, any act of censorship stands against life itself, and is therefore "evil" in the truest sense of the word. That is my belief. It's extreme, it's in the minority, it's completely at odds with yours, and I will firmly hold onto this belief until the day I die.