It wasn't retrospective. It was a prediction, available on the day of the election, and before. Basically, you are talking nonsense, rationalizing your priors.
Oh come on. Silver's polling averages, and his election predictions, were up a year before the election, and are still up for everyone to see. "Retrospective now" doesn't even make sense. Keeping up his model and his averages on the web isn't "memory holing" anything, it's being radically honest. You can still see his 2016 predictions too!
