Why would people who worked for the CIA lie? Seriously?
The CIA's own investigator general has challenged the notion that Khalid Sheik Mohammed and Abu Zubaydah provided their best information only after harsh treatment. And the FBI contends that they got more information out of detainees without the use of harsh tactics.
They are lying to cover their asses and the asses of others in the CIA.
KSM fed them a pack of lies under waterboarding. He sent them off on a bunch of wild goose chases. That was in the CIA's own internal documents which were what the Senate Report was based on.