The U.S. Supreme Court on Tuesday threw out the stalking conviction of a Colorado man who sent hundreds of unwanted Facebook messages to a female musician, ruling that state prosecutors had not shown that he was aware of the "threatening nature" of his statements.
This goes to your point which, hyperbole aside, I think the bar for judging a statement as a threat unless it is unequivocal in its phrasing or the perpetrator literally admits their intent is set impossibly high here. I can’t see how you get a more clear cut situation of where someone ought to understand that their words were causing distress.
In this scenario you literally have the authorities going “what you’re doing is threatening people.” The person then goes on to keep doing that thing, and then somehow successfully fields the defense that “he didn’t understand that it was coming off as threatening.”