When you cease to be a silent citizen/consumer and become an activist of any kind, you are crossing a line. The police recognise this fact and begin to treat you as the irritant you have become to them. In some cases, you are much more threatening than this and the official response is commensurately more severe.
Cycling politics is politics. This is a dirty game. I hope, when you start to come down from your anger, you are still enthused. Respect!