If he'd gone through the official channels first, he wouldn't have gotten the chance to do it another way when inevitably official channels did nothing.
They'll ruin your life either way, at least this way the info makes a splash.
You mean he wasn't capable of gaming out the consequences of the Government reacting poorly to the use of official whistleblower mechanisms and wouldn't therefore be able to go to the press in the manner in which he did?
I disagree. He could have taken copies of the files as insurance before whistleblowing, allowing him to then go public if nothing resulted from the official inquiry.
You believe that the Government could hide/destroy all archival Target Development packages, SIGINT Reporting, Full Motion Video, Tactical Reports, Collateral Damage Estimates, Judge Advocate and other leadership decisional communications, Battle Damage Assessments, Political Communications, and other material about any particular strike in question to prevent the investigation of a whistleblowers claims?
They'll ruin your life either way, at least this way the info makes a splash.