"in previous centuries, would have been shot for treason."
WikiLeaks isn't American and it's main public face isn't either, so by the very definition of the world this isn't treason.
WikiLeaks claims roots with Chinese dissidents. If it had applied the same methods to the Chinese Government then the US Government would probably be portraying WikiLeaks are brave heroes. However turn the spotlight on the US and suddenly it becomes a great international evil.
It's not what you do, it's who you do it to.