It suits the forces of control to find those (or invent them if need be) who can play their part of trouble maker and then characterise everyone in that light.
As far as the authorities are concerned, there is no such thing as peaceful protest that is different to violent protest. that's just semantics. All protest is de facto non-co-operation with the wishes of authority and is, therefore, opposed to the maintenance of order. So it is a disorder that must be opposed. If violence is a useful tool for the preservation of order, then it will be deployed without reservation.
The attack on the G20 climate camp in London exploded the idea that the forces of law and order would co-operate withe protest. There is no real right of protest when it inconveniences the state, and all protest or free speech even down to photography, can inconvenience the state or their operatives.
did anyone expect something different ? keep to the Fen Causeway