The distinction between civil and criminal law isn't terribly relevant here. You can be found liable in civil court for all of the things listed in the first two paragraphs.
Its entirely relevant. Your speech is subject to civil law, never criminal law, because speech is free. If it is somehow subject to criminal law its not really the speech that is, but some other act which the speech is facilitating.
Yelling fire in a theater isn't illegal, but deliberately doing something that will cause a panic is.
It isn't pertinent to the conversation re: europe. Also, it's false, you can be imprisoned for inciting violence (or taking other unlawful action) in the United States. Finally, there isn't a categorical distinction between having speech restricted by a suit brought in civil court vs in criminal court: in both cases my speech is curtailed by law.
I drew the obvious contrast with most of the rest of the world in the parent comment, I have nothing more to say there.
Yelling fire in a theater isn't illegal, but deliberately doing something that will cause a panic is.