It's almost impossible to accept willful ignorance.
When documented, verified and corroberated information is easily available, to see people purposefully avoid reality for the conspiratorial fog of right-wing blogs is just hard to accept. I believe that's why I hammer on TB so hard, and to absolutely no avail.
The 10 or 12 books I've read on the subject, including those of Bush appointees, all tell overlapping parts of the same story, and all are consistent with each other and what happened.
And yet people who claim to be informed haven't touched them. It's simply difficult to accept.