You're stating this very confidently, but I don't think it's a blanket non-extradition policy. In the case of a potential death penalty, it's a clear no, but that's not the case here.
https://www.state.gov/wp-content/uploads/2019/02/10-201.9-Ge...
German constitution, translation to English: - https://www.gesetze-im-internet.de/englisch_gg/englisch_gg.h...
Article 16 (2) No German may be extradited to a foreign country. The law may provide otherwise for extraditions to a member state of the European Union or to an international court, provided that the rule of law is observed.
USA is not a member of European Union nor an international court.