From the Americans perspective, this was all about the embarrassment caused, not so much about the hacking.
Please don't misunderstand me, I'm not defending what this chap is accused of doing, but we must not loose site of their military systems that by all accounts were wide open. Some allegedly, didn't even have any passwords and others with the defaults left in place.
Let's face it, if he'd been a serious hacker, there are may ways he could have used to cover his tracks that would have made it extremely difficult to track him down, as is the case with many modern hackers today.
If that was the standard (at the time) of their systems, they should be very happy he found the open doors, and exposed serious security flaws. At least once you know about it, you can attempt to solve the problem.
There should have been some pretty red faces amongst the military and more than a few investigations into their level of competence - or incompetence depending on your viewpoint.
The "one way" extradition treaty, was never going to go down well in the UK. It's perceived as unfair and very one-sided, but I doubt it will lead to the return of someone extradited that they've already got their hands on.