That's a really fair point, but it's also not a problem unique to any particular technique or process. There is literally nothing you can do via process to protect yourself from bad or actively harmful management. Your only choice is to try and drive them out of the company, or leave.

Maybe the problem is that 5Ys worked great and seemed like a nice process improvement because we had healthy management. I think the reality is - the unhealthy managers who could really benefit from Eric telling them how to be better managers? They're never going to go anywhere near HN or the Harvard Business Review.