Has to be illegal. Threatening Trump supporters with physical harm based on the expression of lawful opinions. People will be less likely to wear a hat or shirt. He is criminally making threats of violence against those who disagree with him.
If you kept up with the Board you would know that the guy was an Antifa agent provocateur who had a long record of doing this crap. See this: https://twitter.com/IngrahamAngle/status/1269235570485661697
And he obviouusly knew the truth about 9/11. He's an evil guy