This was an extradition hearing, not a trial. This seems to have given the judge room to justify a nuanced conclusion that doesn't extend far past this case. IDK if there's much precedent. If there is, it relates to espionage-adjacent cases. That kind of makes sense. Espionage is different to other crimes. The imprisonment is different, and so is the standard for justice. Closed trials & such. This was also true of these extradition hearings.
I have to wonder though, did all the other stuff relating to this saga affect her decision. The odd charges in Sweden. The party-politic aspects to the US' pursuit of him. Also the "time served" aspect. If he's found guilty, the sentence is unlikely to be longer than the 8 years he has spent imprisoned already.