If you discount the possibility that the torture happened (and the Bush admin has all but stated it did), then the Bush admin is guilty of neglect and incompetence for not making the situation transparent enough to negate the accusations in the first place.
"Maybe" they were trained to lie isn't good enough. Knowing that this doctrine of lying exists within Al Qaeda training should have prompted counters to it through careful documentation of all contacts which could easily be made available to IRC representatives when allegations are made. This would be no issue to national security if the subject hasn't revealed information. Careful redaction could ensure national security issues where necessary (i.e. blurring faces of interrogators, muting audio/blurring mouths & documents) -this would all have been sufficient to dispel accusations. This is already standard operating procedure. The fact that it wasn't apparently done is indicative of at least some truth-value to the IRC reports.
Moreover, not all of the IRC report is based on subject testimony. Of that which is based on subject testimony, not all of the subjects would have received the Al Qaeda training mentioned in your link and additional SOP is to keep subjects segregated to prevent consolidation of stories. Therefore, it is fair to accept that at least a portion of the subject testimony has legitimate truth value.