> Merkel tried to reign in Putin with Gas.
The key word there is tried. "wandel durch handel" means "Change through trade" (1). That's what Germany tried, it was a part of their foreign policy.
Now we all know that it did not work with Putin's Russia, but that was not the claim made by Germanioum. It is not nonsense that they tried. Even if they tried and failed.
Sentences often make more sense when you read all of the words in them.