If you read the timeline, you can see that the protests started before the Chernobyl disaster. At that point, no government entity wanted the reactor to go online.
Some of my family members went to protest there when they were younger. Our physics teachers discussed the plant with us on several occasions as part of the mandatory curriculum. I can just say, Germany's relationship to nuclear is and was always characterized by strange concerns about environmental issues and a drive just to oppose something for vague political associations. It's hard to describe, but feels very similar to virtue signaling.