I think the situation is not as black or white.
There are rules, laws or common sense ways to behave or not to behave in evry country, and while it is okay to discuss them and disagree, if you act against them in special areas, you will get trouble.
The protester could have made their point without getting into the officers faces so much
Awhole lot of camera guys, and a whole lot of people troubling the pece of the memorial
Have you ever been to Paris, and tried to walk into Notre Dame with a hat or cap on? A guy at the door will slap it off your head. Had that happening to me.
Or in Venice, you are not allowed to bring your own food to certain areas, because the café-owners want to make a living from selling their goods.
Of course, the excessive use of force and arresting, handcuffing etc without telling the people in advance to either leave or stop the things they do are a scandal.