He's not even making the argument you're suggesting, he's simply trying to explain why the media has such a hard time explaining the motivation behind the whistleblowers and why they end up circumventing chain of command.
No, he doesn't explain that. There's just some hand waving about "the bureaucracy" and "the system". I think it does a disservice to the many real whistleblowers who believe (often correctly) that by working within the system, or at least by working outside it without breaking the law, they can effect meaningful change.
He makes no attempt to explain just what "evil" Manning was fighting by passing along essentially random classified diplomatic traffic, or why Snowden might have felt morally justified in leaking secrets about U.S. spying on strategic competitors. This was not the Pentagon Papers.
