Some people are upset that protesters are being allowed to camp in Freimann Square in violation of the law. But the most important job of the police is to promote public safety, so discretion must be used in situations where normal police actions could provoke violence. This isn't to say that illegal activity should get a pass just because it's nonviolent. Police simply have to do their jobs in a way that minimizes risk to themselves and others.
One way to handle the matter is to issue citations that require the violator to appear in court. Maybe he'll show up and pay the fine, or maybe a bench warrant will have to be issued. Getting arrested after a traffic stop three months after the protest is over is somewhat less glamorous as getting arrested while your friends film it.