Here's the relevant bit, located on pg. 14:
When I last spoke with Beauchamp in early November, he continued to stand by his stories. Unfortunately, the standards of this magazine require more than that. And, in light of the evidence available to us, after months of intensive re-reporting, we cannot be confident that the events in his pieces occurred in exactly the manner that he described them. Without that essential confidence, we cannot stand by these stories.
The fact that Editor Franklin Foer takes so long to spell out the case perhaps (though not likely) seems justifiable on the basis that they claim to not have found any direct falsehoods besides the previously disclosed Kuwait-Iraq mix-up. So he wanted to spell out their investigation. Obviously the whole situation is a terrible blight for the magazine and the errors and poor judgments have been spelled out elsewhere. But, as Gawker points out, he shouldn't have seemed so inconvenienced by the whole thing.
Taking a dig at Michael Goldfarb, The Weekly Standard reporter who broke the story, Foer writes that when Goldfarb called him, "I didn't know him or his byline." Oh, snap.