"Perhaps by "we" he meant the United States of America."
Powell is a single man who can only speak for himself, NOT America. He needs to make clear what HIS mistakes were at the very least before pointing fingers at others.
President Bush was reelected with the most votes in US history WITHOUT Powell. Both you and Powell best remember that or yes, we will be pointing out the facts.
Actually Colin Powell was still Secretary of State when Bush was reelected, and saying "we" made mistakes seems to suggest he is including himself among those who made mistakes. He didn't say "they" made mistakes. If these are the "facts" you are pointing out, then it may help you to learn what a is and isn't a fact. And saying Powell was a failure is not a fact; it is an opinion.