A terroristic threat made on social media is all the probable cause they would ever need. Don’t want the mod-squad at your house? Don’t be threatening to shoot people. And this moron was stupid enough to put it in writing. What is wrong with you people?
Sorry but not all ‘terrorist threats’ are terrorist threats.
And once we remove due process from the mix and allow people’s lives to be upended by arbitrary government action then sooner or later some SOB in government will find a way to pervert your well-intentioned idea into something where they spy on everyone, search everyone, and imprison everyone any time they want...in the name of ‘security’.
As the wise old saying goes: “Those who would trade liberty for security often end up with neither.”