Those 'protestors' are all fine and dandy until they hit an innocent cop in the face with a brick.
We've had these 'protestors' in Europe for decades, they are actually highly organized radical leftist street fighters, the likes of which were likely used to train rebels on Maidan and in the Arab Springs.
These people travel from country to country and occasion to occassion with the sole purpose to create trouble. There are countless of documentaries made about them, calling themselves different names, the largest which gained traction was Attak (can't remember the spelling).
These are fifth column marxists who need to be rooted out unceremoniously and viciously before they descend upon a city near you.