Cynic that I am, I think it was because Bush had a hard-on for Iraq before
he took office, and directed his staff to cook the intel so he could
justify his attack to the American people. That and the fact that
he had dead-ended in the hunt for bin Laden in Afghanistan.
Why even spend time in the kitchen? They don't need to cook the intelligence
when it's just as easy to ignore it.
Remember the metal tubes that were supposed to be perfect for use in a
nuclear facility? Our own scientists (Oak Ridge Laboratory) examined samples
and said "Great for artillery barrels, useless for nuclear facilities". The
IAEA looked at them and came to the same conclusion. But, Bush still used
them in his list of excuses. Remember?