Which international treaties were ignored by German courts in these cases?
Note that the courts didn't ignore those treaties and or somehow ruled they weren't enforceable. They just have a different interpretation of the legal contents of those treaties than the PGLAF does. Law is often not black or white and anyone who claims there is just one true position doesn't tell you the whole truth. The issue is actually pretty interesting legally and there is a lot more subtlety to it than the claim that courts are somehow bending the law.