Answer is simple. He convinced 8 of 11 jurors he knew nothing about the Final Solution and AT THE TIME there was no evidence to the contrary. OR ... there was enough reasonable doubt in the minds of 8 jurors that they did not vote for death. Surprising considering the lynch mob show trial the Nuremburg Trials were.

Rudolph Hess also got over when he was 2nd only to Hitler until his screwy butt decided to fly to England and negotiate a deal with the Brits

A more interesting question to me is why the Mossad didn't go after Speer. If the Mossad didn't go after him, there must have not been much proof at all considering they wouldn't hesitate to kidnap Nazi's and drag them to Israel for trial.

Sometimes bad guys get over.