Arrest him for terroristic threats - inciting a riot.
Kinda what I was thinking, sounds like a threat. During the ferguson fiasco the local amish here in NE Fla. tried blocking a couple of our bridges around the afternoon rush hour, once. The Sheriff’s office put a stop to that immediately and with a quickness. That same evening our Sherriff came on all local news channels warning that type of behavior would not be tolerated here AT ALL and would be dealt with accordingly. Those who tried it the 1st time went to jail, appeared in front of a judge and went back to jail........it hasn’t happened since.