"Posts on a public site...Complains about privacy"
What the hell you are going on about man. If you post something like "Hey, lets shoot some cops", or hell "lets start shooting ____" online you are giving up your right to privacy. Yes, the US legal system has means of taking the 'evidence' you posted online in front of a judge and getting a warrant. Via the warrant system nearly complete dismantling of your privacy can be compelled.
Neither of those things would be a basis for something like a search warrant because the threat is not specific and credible. It's not a crime to say, "Hey, let's shoot some cops". It would be a crime to say, "Hey, let's hang out in front of the local police station and shoot some cops tomorrow morning. Bring your guns."
In your imaginary world. In the real world telling the difference between a non-specific and credible threat commonly takes investigation, especially when one of the parties is brought up to law enforcement multiple times.
In addition law enforcement agencies, especially the local ones, are based on the whims of elected officials. If the local populace thinks they they aren't being tough enough on crime, then especially in smaller cities, they will be replaced.
What the hell you are going on about man. If you post something like "Hey, lets shoot some cops", or hell "lets start shooting ____" online you are giving up your right to privacy. Yes, the US legal system has means of taking the 'evidence' you posted online in front of a judge and getting a warrant. Via the warrant system nearly complete dismantling of your privacy can be compelled.
Play stupid games, win stupid prizes.