I know Brian Williams slightly; have always liked his on-air presence; am glad he has participated in Atlantic events, like the one shown above; and am sorry for his current "our helicopter was hit" difficulties.
I don't mean to compound them, but I want to explain why I find the episode mystifying when it comes to human nature, and revealing about our current politics.
Mystifying: Memory is tricky. So is presentation-of-self—as David Graham explains in an item just now.
But with all such allowances, I still find it just about incomprehensible that someone: (a) whose professional background involves observing and reporting events, (b) who holds one of the handful of jobs in the world most reliant on trustworthiness, and (c) who knew he was talking to an audience of millions of people that would (d) include others with first-hand knowledge of the incident, would nonetheless (e) "misremember" what must have been one of the most dramatic and traumatic moments of his life, after (f) accurately reporting the event for the first few years after it took place, and (g) when the whole thing is only a dozen years in the past, not somewhere in the fog of distant childhood memory.
Again, narrative and recollection are strange. I think I clearly recall vivid or traumatic episodes in my life, starting with the time a pickup truck rammed the car in which I was riding with my mom as a pre-schooler in Jackson, Mississippi. I believe I'm sure that I was sitting in the front seat, in that era before seat belts or child safety-seats, and just missed hitting the windshield, being stopped by the padded dash. But maybe, this many years later, I'm fooling myself. There is no one else around who was there. Three or four times in the past 20 years, I've been in uncomfortable situations while flying an airplane. I think I could recount those episodes in second-by-second slo-mo detail. But I can't be absolutely sure.