So he gets into a minor argument with some security guards, guards call the cops, cops leave their business card on his front door and when he calls them he's asked if he's been to Boston recently... what am I supposed to be outraged about?
The FBI are cops - federal instead of local. Still, what's your point? No arrests, bullying, massive surveillance... They obviously didn't take think he was a threat, or else he wouldn't have showed up and left his business card. The agent was just following up on a routine report. Is it a violation of civil liberties for a cop to ask questions?
"Is it a violation of civil liberties for a cop to ask questions?"
If it's questions about your life and the cop doesn't make it clear that you can refuse to answer without any consequences, then yes, it very much is. Part of civil liberties is that you don't have to explain to anyone how you live your life unless there is some good reason to believe you did something illegal.
