My only response would be (1) to point to the date of when he said that compared to the date of the final manuscript, and the all the conversations that occurre

My only response would be (1) to point to the date of when he said that compared to the date of the final manuscript, and the all the conversations that occurred n between. I think that was from sometime in January. (2) we shouldn't read over-much into an off-the-cuff slack message, ostensibly shared with a small number of individuals, with his impressions and thoughts at the time. The purpose of those discussions is to bang ideas off the wall. In any case, I don't expect good scientists to rigidly hang on to an idea. I expect good scientists to evolve their thinking as they learn. But you may be right that the published paper did not speak to what their particular priors were when they started out. I'm not certain that we should expect it to either. A lot of times you start off with ill-formed half-ideas, and while they may be where you started off from, the utility of sharing that starting point might cause more confusion--or even spread more misinformation--that do good.