I think you are missing a point though. Who is best placed to judge what to release? The leaker, or experienced journalists? What if you know there are more abuses but don't have time to individually search through the documents before leaking? Should you only take the ones you have already read, and lose out on revealing other abuses? It's a difficult choice.
From my outside point of view, the government (and often media) errs too much on the side of secrecy so I'm glad to see a whistleblower who is more aggressive with the amount of information they leak.