It's the closest thing we have right now to a Truth Commission, and Americans have a right to know and understand how a secret law allowed illegal torture came to pass. Even the establishment WaPo agrees:
Investigations of this type are usually kept secret unless and until the investigating entity determines that wrongdoing has occurred. There's a certain logic and decency to this: Mere news that someone is under investigation is often enough to tarnish that person's reputation -- even if charges ultimately are not brought. Yet the existence of the investigation and many details of the OPR report have already found their way into the public arena.
For example, The Post and other news outlets have reported that the OPR will recommend that Judge Bybee and Mr. Yoo be referred to their respective bar associations for possible sanctions. The best way to proceed -- both to ensure fairness and to fulfill the strong and legitimate public need to know how questionable policies and legal opinions came into being -- is to make all material relating to this investigation public, regardless of the Justice Department's findings. Documents that should be released include the full OPR report, all submissions by the subjects of the probe, and the letter written by former attorney general Michael B. Mukasey and former deputy attorney general Mark R. Filip that criticized the draft report.