This man's facebook post alone, and especially absent of any kind of access to a gun, are no grounds to assume any actual intent to cause physical harm. Far from it, I would say artists who have a history of violent confrontation, write/sing/rap about stabbing, shooting, or otherwise assaulting other people, and actually are in possession of weapons they could use to do so, could be assumed by any reasonable person to be more guilty of actually having an intent, or at least an overzealous willingness, to cause harm to others.