Actually, it gives him a plausible way to deny any responsibility for anything he said after that, allowing him to say whatever he wanted to to prove his point without actually having to give proof. If there is proof that this was supposed to be a confidential, off the record conversation, he can make up stories without having to prove anything. Stories that could be spread as rumors without him being held responsible for anything he said or implied. Otherwise, he would have to be ready to stand by what he said, and have a way to prove it.
Sort of, but not really. Learned early on in my practice never to put ANYTHING in writing that you did not want to see blown up on a 4X6 board and shown before a jury. I agree wholeheartedly with this statement. If you want to relay information that you want to otherwise be able to deny or you don't want to be on record somewhere, the only real way to do it is via the telephone or in person (and even then, if it's being recorded you're screwed).
ETA: My suspicion is that he was going to call out other folks, say stuff he did not have particular proof for, etc., but that by restricting my ability to repeat it or conversely strictly noting that the information was not being provided for my personal benefit and not for "public dissemination" that he would be limiting potential liability for libel or slander which, IIRC, requires that a statement be "public" to be actionable.