Your understanding of the facts are masterful. It's the ability of Americans and particulary their government to rewrite recent history that's at fault.

Yes America strongly hinted that Iraq was connected to 9/11. They could even name 1 terrorist (not from Al Queda and wanted for a nearly 20 year old terrorist offense) who Iraq was protecting.
Yes America now admits it had and has no proof that Al Queda was ever associated with Iraq.
Yes 70% of Americans believed Iraq was linked to Al Queda.

we could even add

Yes America claimed Iraq had WMD
Yes America still has no proof of such claims

thus removing the need for the 'adequately protecting the US from ...' in your quoted article.

Paul.