I think ya'll are both right. On the one hand, you're right because "just manage better" is a silly assertion. As you say it is like "just don't be poor", or the one I think is more relevant to this conversation: "coal miners should just learn to code".

On the other hand, however, these are in fact business leaders who have written books about how good they are and how much they know about leading people, so... it's reasonable that our expectation of good leadership is a bit higher for them than the average middle manager.