that's the ideological answer. The material one is: the German economy was dependent on cheap gas from Russia and cut that off. It reveled too much in becoming America's sub and said yes, mistress to everything the US did to weaken Europe and especially Germany, making it cut ties with Russia and letting the US blow up the pipelnie without saying a word except "please, may I have more."

It thus helped the US start to re-industrialize itself after decades of pure financialization (through massive government subsidies), by drawing energy-intensive German industries to other countries, also the US, while ramping up oil and gas production in the US, selling gas at quadruple the price to Germany. The US now produces more than Saudi Arabia.

After losing much of its influence in its former neocolonies in the global south, the US thus now turns Europe into a neocolony, the only place on earth that still kneels before empire. In the wake of this, Germany is also slasing its welfare stae in ways unseen in history ... because it needs the money to send to Ukraine. (The Ukraine aid is not getting cut, while child care credits, welfare payments, energy subsidies to poor households because of the high gas prices, etc. all are.

Sure, there's also the folly of turning off nuclear power plants and investing in inefficient wind turbines, and in solar which is now much cheaper and better in China than in once-leading Germany. But compared to US imperialist conquest, this is a second-rate concern. Still a concern, but not the main one.