See, I am not necessarily talking about the USA as I am from Europe. But I value the universal right of the western world for free expression very much. There is no such thing as the perfect country, but I firmly believe that you should have the right to freely discuss shortcomings and solution. This is given in the USA as well as in Europe. You will not have that possibility in Iran or China. And you will have many other things denied, too. So good luck there!
The 'universal right of ... free expression' that you mention is not quite universal. One does not simply have the right to declare that all members of [insert group] should be [insert unpleasant fate's verb's past participle]: there happen to be hate speech laws... similar situation for slander. That's all very well, but then one finds that anti-Iraq War activists have those same provisions used upon them. What's to stop governments from extending this further and further until we find that we are in an Iran or China like situation? It's not particularly likely but it is still possible, given the situation. Not implying that situation in Iran or China or any other similar countries is comparable to that of much of Europe, though. Just suggesting that there are limits and that the question is how far these limits go, not whether these 'rights' exist at all. In Iran/China everyone is free to support the government, hence very limited free speech.
The fact that you can't legally say anything any time you want does not imply that there is no legally protected right to free expression. It isn't a slippery slope to a dictatorship.
"We should gas all the Jews, rise up with me" isn't just free expression. It is also an act with predictable consequences.
The most likely consequence would be the antagonist getting shouted down and shunned.
If you have to worry about a pogrom breaking out as a result of inflammatory speech then you likely have deeper issues to worry about.
See, I am not necessarily talking about the USA as I am from Europe. But I value the universal right of the western world for free expression very much. There is no such thing as the perfect country, but I firmly believe that you should have the right to freely discuss shortcomings and solution. This is given in the USA as well as in Europe. You will not have that possibility in Iran or China. And you will have many other things denied, too. So good luck there!