My personal & anecdotal experience has been that there are just as many managers who fail to engage well with draft-work as there are those who want to chip in their 2 cents on everything. There is definitely a class of managers who think they're offering encouragement but are so focused on the end goal that they fail to show respect for what has been achieved so far.

Of the two, I prefer those who offer unnecessary input to those whose only response is something them amounts to "is it ready yet?"

I would hate to see people read this advice and move from the first group to the second group without realising that they've traded one set of problems for another. I am quite confident that that is not Sivers' intent, but I think it is absolutely a gap in his post.