So I would say that 'Freedom of Speech' is more cultural than legal. Which is fascinating to me because it's such a big deal in America, and Americans 'defend' their freedom of speech.
You have to look at our history and the political system that we came from to fully understand our defense of our freedoms. It was necessary at the time to codify them to prevent their loss at some point in time. We simply did not want our political system to devolve into that which we experienced under King George. The steps we took and the level in which it is ingrained in our system of laws and psyche ensure that.
Still, no level-headed citizen of the United States thinks that these freedoms are without limit.