He didn't want anyone to learn that he had unilaterally destroyed his WMD. That knowledge would have ruined his bad-boy image.
You mean he didn't think that mass murders, public beheadings for small transgressions, imprisonment, torture, rape, maiming, etc., would be enough to keep the Arabs from thinking he was a sissy? Heck he was paying millions to journalists, including al Jazeera, for an ongoing PR campaign. You may be right, though. I guess one can't have too much of a good thing.