Yelling is not a crime
I don't think that's even true.
Remember a couple weeks ago when some leftist woman caught Steve Bannon in a used bookstore and was howling away at him? The bookstore owner called the cops on her and she disappeared.
If someone started howling and shrieking at me in the middle of the supermarket, don't you think they'd call the police? It's threatening, it's disturbing the peace --- yeah, it's against the law and it ought to be. I'd call the police: help definitely needed.
This guy was definitely breaking the law terrorizing this woman and little kids in the parking lot; he just thought he could get away with it.
I guess he did, too, and achieved his lifetime ambition of killing someone.