No, that’s not what democracy is all about. It’s also not true. There are democratic states other than the U.S. that don’t share our lenient views on free speech. And dictatorship is not defined as a state without free speech.
What you say about suing as a civil case is true, but irrelevant. My point is since such an instance of free speech is prosecutable, it cannot be protected. The particulars of the forum and mode of redress do not change this.
Also, it is not always treated as a tort. Many countries prosecute defamation as a criminal offense. Several states in the U.S. also have provisions making it a criminal offense.