I'm not sure Assange is a criminal, but why people would consider this admirable is beyond me. It's basically just f***cking with the system for its own sake. There's always going to be a distinction between public and private diplomacy, and if the risk of leaks increases, staff will just go even more off the record and phone each other rather than writing things down, and things will become even less accountable.
The phrase "real-life troll" is overused, but Assange is basically a paradigm case.
This sort of stuff wasn't like Wikileaks was started though.