I mean, he kinda did. I am a liberal that is perfectly fine with some exercising their rights. If he was wrong they would have showed ID and arrested him. Although a lot of first amendment auditors lean right/far right I still appreciate what they do.
Not sure what you are saying here at all? It is not in the first amendment to protect anyone from instigating or encouraging injuries/death to another. They could arrest and detain him and confiscate his computers and start an investigation if they wanted, that just costs more, so they likely are following a protocol of dumb fuck says dumb comment. Start remote investigation. Find something more, make sure he knows they're aware. If he persists things will escalate