US National Security Agency buys web browsing data without warrant, letter shows

They have a mandate allowing electronic observation of foreign nationals activities and filtering out US citizens.

Someone posts a threat on FB, tell us exactly how you would filter it and remain in compliance.

They have a history of looking at things like this and cross referencing the data points with known protestors or online figureheads to build files against them. It makes it easier to dismiss a case when you can build a narrative that someone is mentally unwell or biased, or to incite action by making them out to be a threat. The protesters against Atlanta's Cop City who were charged with RICO violations had such a case built against them by using their communications on social media for example.