Assange did not steal any US secret files, US citizen Chelsea Manning did. Assange did publish them.
In Australia, he received a Walkley Award in journalism for it.
Assange was not in breach of any Australian laws at the time of his actions.
Assange was not in the US when the event being deliberated in a court now in London occurred.
The question is then: Why is he to be extradited to the US? If he insulted the Koran, would he be extradited to Saudi Arabia?