Shit breaks out. If you look hard enough online, you'll even see her getting pushed in the crowd by police.
I'm presuming what happened was that the police treated her differently for being a known figure, with a lot of power in their voice once in custody. Make a couple wrong moves with her and your going to have a PR disaster like no other. So when people pulled up the camera's I'm assuming they just allowed it for a little bit. As other people were not treated nearly as nicely as her.
However she still got arrested. Which is something conviently ignored, almost like the thing your accusing of people your doing and having to lie to create your point.
This was a protest that lasted severely weeks trying to protect a village of 90 people roughly from the government of Germany trying to forcefully removing them for coal mining. It was one of Germany's last remaining villages. Greta among others said they'll protect them as long as they could. And it worked for a while, up until recently.