What are you talking about? There are obvious and practical limits on 'free speech'. In fact, the Supreme Court has unanimously upheld a "fighting words" doctrine ensuring that speech which is by its nature injurious or likely to cause breach of the peace is not protected.
An excerpt from the 9-0 decision makes a pretty concise case, especially the latter part:
"Allowing the broadest scope to the language and purpose of the Fourteenth Amendment, it is well understood that the right of free speech is not absolute at all times and under all circumstances. There are certain well-defined and narrowly limited classes of speech, the prevention and punishment of which has never been thought to raise any Constitutional problem. These include the lewd and obscene, the profane, the libelous, and the insulting or 'fighting' words-those which by their very utterance inflict injury or tend to incite an immediate breach of the peace. It has been well observed that such utterances are no essential part of any exposition of ideas, and are of such slight social value as a step to truth that any benefit that may be derived from them is clearly outweighed by the social interest in order and morality. 'Resort to epithets or personal abuse is not in any proper sense communication of information or opinion safeguarded by the Constitution, and its punishment as a criminal act would raise no question under that instrument.' [Cantwell v. Connecticut]"
https://web.archive.org/web/20080906001323/http://laws.findl...
We can argue about definitions of 'obscene', 'likely to cause a breach of the peace', etc. But to treat freedom of speech like an unassailable, all-or-nothing fundamental assumption is not helpful.