The problem is that the US in its international relationships never cares about any laws, normal or otherwise.
In this case they demand the extradition of Assange for supposedly having done some minor crime, but in the past the US have refused to extradite their people wanted for major crimes, like manslaughter, which were proven beyond any reasonable doubt.
For example, one of the cases that I am aware of happened some years ago at the US embassy from Bucharest, Romania.
Someone from the military personnel of the US embassy has driven a SUV while drunk and he hit a taxi cab killing the passenger. The American ran away from the accident place and in a few hours he was smuggled from the country by the embassy, so when the police came in the morning to arrest him he could no longer be found.
There was absolutely no doubt about his guilt, but nevertheless the US refused to extradite him and he was never punished for taking a human life.
There have been many such cases with US citizens in many countries, so whenever the US demands that other countries should extradite their people for supposedly breaking US laws, the US government shows extreme shamelessness, by asking others to do what the US will not do.
Unfortunately there are many servile foreign governments who accept this asymmetry in their relationship with the US.