There is a material difference between 'Whistleblowing' and 'Stealing and Releasing Data Because You Want To'.
Those releasing documents regarding arbitrary imprisonment of people because of their ethnicity are 'Whistleblowers'. I would argue that the release of the video showing US accidental killing of Journalistgs in the friendly fire incident, may fall under that.
But the diplomatic cable leaks I don't think constitute whistle blowing.
"Laws are basically just threats,"
Total rubbish, I can't fathom that someone would believe this.
The Law is the most foundational aspect of civilization, probably more important than democracy itself.
It's a set of codified rules that we roughly agree upon, or at least are aware of, that we are all equally subject to, not one above the other - or at least it's supposed to be, and when it's not, we consider that a form of corruption.
Assange is possibly guilty of the crime of breaking into private government systems to release arbitrary data to the public, which is probably a crime.
When the trial starts, we'll get to see the evidence, one of the advantages of living in a Western Liberal Democracy is that most of this information is available to anyone, another key aspect of a functional Judicial System BTW.
Regardless, laws are completely irrelevant to what's right or wrong. Laws are basically just threats, and it's not wrong to do something just because someone threatens to harm you. It doesn't matter if that someone is the Chinese government, the US government, the Taliban government, or some local street gang.