He published information that "could aid the enemy" and "damage own personnel". According to the military, that's a crime, even if (or moreso if) it's done by revealing war crimes committed by the military itself.
He also published, and was about to publish more, compromising information about a bunch of other people who have lobbying influence over the US government.
And he has got multiple awards... just not from the people he's pissed off 🙂
He published STOLEN documents. If you want to participate in Civil Disobedience, you have to accept the consequences. He's not in it for any cause other than fuck you.
By that same logic, can Russia ask Japan to extradite a US citizen because they advocated for LGBTQ+ rights while they were in South Korea? Because that's basically what's happening here, I just swapped the offence and the countries involved.
Dude isn't a US person, wasn't in the US when he committed the alleged crime, and said alleged crime isn't a crime where he allegedly committed it. US law isn't world law.
EVEN IF the guy might've been rapist asshole (allegations were fishy as heck), this extradition proceeding is a gross overreach by the US, and the UK should have laughed it out of court. If a country has any leg to stand on regarding extradition, it's Sweden (I think that's where he was when he committed all the alleged crimes, both the sexual ones and the wikileaks ones).
They can ask, but no one is under obligation to comply, just like the US asked and were rejected. If I personally published stolen classified material that would embarrass or materially harm a foreign nation, I would expect retaliation of some sort.