Yep the problem is the "hurting" part. A common medium of demonstration in Germany, historically, has been the Sitzblockade (people sitting down blocking eg a road). Now, resisting when the police tries to clear up such a Blockade quickly gets you into stgb art. 113 territory, in the current state of affairs. I expect the same to happen to many of the protesters mentioned in the article.

Edit: to be clear, I'm not saying one should attack the police. I'm saying an "attack on the police" should be extremely well defined, since otherwise people can be charged with it for arbitrary transgressions, which effectively scares people away from necessary protests.