Apparently much of the memo talks about how much editing a Times story undergoes, a process that certainly existed 13 years ago. If all these editors didn't catch Blair, what value are they adding?
Editors at newspapers may well ask hard questions about how well sourced an article is--as well as making lots of other changes to improve rigor and readability. But, as in the day-to-day operations of many professions, they tend to assume that the journalists aren't actively lying about things.