Forget all the waffle about who did what as all it is about is can the
United States enforce their laws in other countries.
Extradition is for people who break laws and are now located in another
country.
That is the law.
Yes things are different due to the internet but that does not change the law.

From memory, Bazz, Australian paedophiles in Australia can be prosecuted in Australia for having committed crimes against children in other countries, such as the Philippines.

ISIS fighters can be prosecuted for being soldiers of a hostile political entity, in another country.

It is in fact illegal in Australia for any Australian citizen to take part in military actions overseas, without government approval. Although just who is fighting who seems to be a mitigating circumstance. If you kill for the Kurds or the Israelis, that's OK. If you kill for the Russians, the Rhodesians, or ISIS, not OK.

I believe you are right about that Lego on the military activity.
On TV last night a Nigel Phair of UNSW based in a Canberra office,
seems to be well connected on cyber protection etc.
stated that there is an agreement between a number of
countries, EU Aus, NZ UK, US Japan etc on Cyber crime that where those
countries have compatible legislation a cyber offense committed in one
country against another country is tried by the first country.
So if Assange at the time in the UK or Australia committed a cyber
crime by hacking or assisting a cyber crime in the US he must be tried
in either the UK or Australia depending on where he was at the time.

That did seem to be a definitive indication of the situation.

WIKILEAKS THREATENS COURT ACTION - ATTEMPTING TO CENSOR JOURNALISTS' FREEDOM OF SPEECH

In a move to prevent real journalists from doing to Wikileaks what Wikileaks does every day to Democratic governments, January 7, 2019 http://www.pressgazette.co.uk/wikileaks-emails-journalists-with-97-false-and-defamatory-claims-to-avoid-in-reporting-on-founder-julian-assange/

Wikileaks emailed journalists with a list of 97 “false and defamatory” statements about its founder/publisher Julian Assange after claiming efforts to defame him had “reached a new nadir”.

It said the number of “false and defamatory” claims made against Assange had “accelerated” since his internet access at the Ecuadorian Embassy in London, where he has lived for more than six years, was cut off last year.

This rise was “perhaps because of an incorrect view that Mr Assange, due to his grave personal circumstances, can no longer defend his reputation”, it said in the email sent out to journalists.

Before listing 97 “false and defamatory” claims about Assange and Wikileaks itself, the email concluded: “The purpose of this list is to aid the honest and accurate and to put the dishonest and inaccurate on notice.”

It is believed that the list originally contained 140 claims, but the version published by Wikileaks today had some sections taken out."

WIKILEAK'S ITSELF PLACED A SECURITY CAVEAT on its Email List as “NOT FOR PUBLICATION”

But Wikileaks was forced to make the Email List (reproduced here http://pastelink.net/m69m ) public after the List was

LEAKED by JOURNALISTS who DEFIED WIKILEAK's LEGAL THREATS.