Oh no that information is readily available, indexed, ready to be brought up at a moments notice as soon as they have someone new on the radar. They can crunch through that data very quickly to generate a threat assessment on a new person. For the government, the difference between trolling and real threat don't matter, they treat them the same until you are about to do something. If you've ever made a joking threat about a politician on the internet, there's a file open on you, it just may not have your name on it yet.

It's not about predicting, it's meant to be retroactive once they have a person in mind. That's what makes the data collection technically legal according to the courts, since no specific individual is being targeted by the mass data collection, no warrant is necessary. They can gobble it all up now, and sift through it later.