In the US the way things were originally set into law, words are separated from action. People can say things they might not mean, but unless there is credible evidence of an intention to follow words with actions, there is the ability to forgive. Not forgotten, because once something is said it cannot be unsaid, but forgiven. At least that's the way it is supposed to be. That has been twisted so much that it's difficult to see beyond the shades of gray.

And there are court defined limits, like yelling fire in a theater and other such things. The main source is the 1st amendment, which is not actually a limit on the people, but a limit on the ability of the government to persecute the people for what they say. Given that we broke away from the British Crown, it was important to put into law the idea that dissent against the government is different from actions against the government.