It's worth pointing out that the victim probably isn't in social circles where the government killing people for no reason all the time gets much attention. Hyperreality is a serious thing, the guy's worldview probably makes it seem like free speech exists, unless it's a bad slur on facebook dot commie.
The guy openly posted that the FBI wouldn't dare raid him because they'd get a 45 ACP in the face. I'm no law enforcement apologist but that kind of boast can put people on edge.
Specific threats of violence should never be acceptable.