I feel like you took only half of my point. If the manager is good, then there is no reason to bullshit them. But believing that a bad manager will suddenly become good because you as a report taught them with a few carefully-crafted politically-correct statements sounds extremely naive to me.

Let me give an example: to a good manager, you could say "I'm under a lot of pressure because I have two many urgent things on my plate" and they should try to improve your life by maybe de-prioritizing some of them. In a way you gave feedback "it's not going well for me", but you did not try to guide your manager in their role. So that's not the kind of feedback the featured article talks about.

Now a bad manager will maybe be nice and say "I understand, I really appreciate the late nights and weekends you spend getting closer and closer to a burnout, you are a really valuable employee to me", but that's completely useless. Trying to tell them "you know, in a previous job I had a manager who in these situations would try to de-prioritize stuff so that I could live normally" is completely useless. If they aren't doing it yet, it means that they should not be your manager in the first place. Best case they say "thank you for the feedback, I appreciate that you feel comfortable speaking up" and don't change anything, worst case they get pissed because you "overstepped" (they are the manager, they know they know better, remember?).

There is no world where they say "you're right, I sucked until today, but from tomorrow on I will magically know how to be a good manager".