There's a vast difference between a whistle blower leaking information or exposing government corruption and the mass release of confidential diplomatic and military messages. Mass release of messages is laziness, since many messages that may be embarrassing are not bad (people gossip all the time), but instead just make the US or diplomats look worse for no reason, and military messages may potentially give away information that leads to troop death.
I believe leaks from wikileaks exposes government abuse, which is very secretive in its dealings. The citizenry have little idea what the machinations are behind foreign policy. I believe they are secretive because they believe the population would not support much it. The leaks bring to light some of these abuses, such as war crime, and spur on national debates.