I guess it is a slippery slope on a path towards someone yelling "fire" in a theater when no such threat exists and as a society we determined that that is not acceptable. It would have something to do with intent to mislead, harm or knowingly distort some truth. We see "truthiness" and its damaging negative effects on society. Also "free speech" in the constitutional sense is to protect you from government prosecution but it has limits. It is not a license to say anything you want in any context anywhere. Society imposes editorial control through law and order. And by order I mean through organized groups of individuals.