The alt-right depicted here are "clowns" as described by Bannon, but even "clowns" have the constitutional right to demonstrate peacefully, as  the Supreme Court  reaffirmed again specifically in this case.

And the clowns spouting "we shall not be replaced" are responding to the alt-left clowns gloating and cheering at the prospect of the disappearance of the "evil white" race to be replaced by the supposed intrinsically morally superior "brown" races.

Those clown fringes are both clowns and mirror images of each other. Letting them go at each other while cheering one side on  just escalates the situation. They both need to be condemned.