I originally thought intelligence failure meant a failure to anticipate.
In reality it means a failure to be intelligent.
Beyond the fact that Tora Bora was meant to be a Deep Underground Military Base the CIA built for Al Qaeda (
https://en.wikipedia.org/wiki/Tora_Bora#Military_base ), it seems more likely that the CIA was defrauded for something that seems impossible; the ability to conduct a massive construction project in Afghan territory when they were a Soviet client state.
Or that some woman, who after being alleged that she attended a sex party including children, was later found to have been attending a sex party including children, to somehow be in continued denial of that shows a sort of stupidity beyond my comprehension.