With a few exceptions (so-called "fighting words") vulgarity IS protected speech. What this woman said falls under the First Amendment.
From http://www.firstamendmentcenter.org/analysis.aspx?id=18508:
Almost 30 years later in 1971, the high court limited Chaplinsky in Cohen v. California by holding that an individual could not be held criminally liable for wearing a jacket into a courthouse that said "F*** the Draft". [my note - the jacket had the real F-word ] The Supreme Court distinguished the two by explaining that Cohen's action was a "simple public display" as opposed to a direct insult or intent to incite harm, as was the case in Chaplinsky.
Just because a black-robed potentate says it is doesn't mean that has anything to do with original intent. I don't know about you, but I think it's long past time we stopped acting like it does.