They are not protest permits. They are protest announcements. The only requirement is that protest organizers need to inform public officials beforehand that they are going to hold a protest on day x at place y. Consequently public officials are able to prepare conditions to ensure a) the protest can be held and b) counterprotests cannot interfere, c) neutrsl third parties (that is, people who wish to go on with their lives as they didn't want to participate) are not forced to be sucked into the mess.

And once announced public officials cannot stop a protest from happening.

Otherwise we would see football moorings being described as peaceful protests under free speech instead of what they really are.