Rewatch the incident in the clip I've posted and you'll see that Bairstow ducks, the ball passes over his head, Bairstow at no point thereafter looks behind him to see what has happened to the ball. He doesn't even watch it into the keepers hands. For all he knows, the keeper could have missed the take, dropped the take, it could be going for byes, in any of these scenarios the ball would have been alive and Bairstow wouldn't have been any the wiser.
For argument's sake, what if the keeper had dropped the take, Bairstow had walked out of his crease, the keeper had picked up the ball and thrown it at the stumps?
At the very least it was sloppy and gormless cricket from Bairstow.
If anyone wants to look at the link I've posted, it shows that at no time was the ball settled in the keepers hands. He receives the ball and throws it at the wicket in one fluid action.
There was never a pause or hiatus in play.
There was only one person to blame for Bairstow losing his wicket, and that was Bairstow.