Obviously you enjoy ignoring the facts. The judge was bound by the agreement because
he originally agreed to it. Then, because of pressure, he decided to change it.
The original agreement,
which the judge agreed to, included the sentence.
Polansky served the sentence
the judge originally agreed to.
The judge made it clear that he was going to ignore
the agreement that he had already agreed to and give Polansky a sentence that would save the judge's political skin.
The Swiss, by law, can't extradite someone who has served their sentence. The question then becomes, was there an agreement and did Polansky serve the time agreed to. The evidence they had in their possession showed there was an agreement and Polansky served the agreed sentence. They then asked for other documents that could show there was no agreement and Polansky had not served his sentence. The US refused to unseal the documents so the Swiss had no choice but to go with the evidence and release Polansky.
I suspect that the US was as eager to let this go as Polansky was. There are only two scenarios for the judge, stick to the agreement or don't stick to the agreement. Either way the US justice system was going to look pretty pathetic. At least by not revealing the documents, the US can keep everybody guessing as to why their system is a joke.