I kind of agree but you can't be absolutist either. If a mob boss says "kill this guy" to one of his hitmen, and the guy kills him. Only the hitman goes to jail? The mob boss just used his freedom of speech but didn't act?
But we should not ban speech when there has not been any crime.
For the mob boss, he is committing an actual crime of extortion. If a shopkeeper goes to police, the mob defense would not be "we were in our rights to threaten", but "we never said this; no idea what the shopkeeper is saying". A prosecutor would have to prove that it was indeed an extortion, but if he proves this to a jury the specific words said would be irrelevant and a first amendment claim would fail.
The same way if an insider is telling a friend about a stock merger during a quiet period, it is an actual crime. The specific words and methods do not matter.
It is tempting to restrict the speech in an attempt to minimize the evil. But giving state this power sooner or later vests it in some political clique that will use it for political suppression; original noble goals be damned. And this is almost impossible to undo.
He could just go ‘i really don’t like this guy’ and that would be understood at ‘kill him’ without him saying. Would that be ok or you still would want to prosecute him?