The UAF do exactly what their philosophy says, they group to protest against fascism. Now, people have different views on who's fascist or not etc, and of course the fact they turn up will create tension, disruption and extra policing costs no doubt. Whether you or i agree with that is neither here or there, they've got the right to protest.
They could argue that the original protest shouldn't be happening in the first place, sheite this democracy aint it.