Is Germany a direct democracy? If instead it is a Representative Democracy then I would expect my Representative to act in my interest not on my whim.
I am not too familiar with the ins-and-outs of Germany's politcal system though it appears to be a popular position.
https://www.dw.com/en/merkel-shuts-down-seven-nuclear-reacto...
https://en.wikipedia.org/wiki/Angela_Merkel#Chancellor_of_Ge...
Regardless ending nuclear power in Germany is a popular enough position that Merkel was re-elected. Probably not just on that issue but she listened to what her people wanted and she kept getting elected because of it (as far as I know; I'm not German).