Astonishing. Completely backwards. This article describes how to give feedback to your subordinates, not to your superiors. If your superiors are unable to process no-fluff information, regardless of whether it's feedback or updates, they have no business lording over anyone and will sink whatever function they have oversight of. If you find yourself working under such people, don't bother giving feedback, start poli…
Much of their examples are a kind of diplomacy that you might use with a somewhat hostile, stupid, and/or petty person. Not in an environment of trust and respect.
Or with an enterprise customer, where "business politeness" is expected, trying to gain advantage is expected, and no one expects you to be very honest.
(Exception: In some cultures, it might be outright rude and mutually awkward to ever say anything critical-sounding upwards, or to offend someone by not going through the politeness motions, which would just be disrespectful. The article seems to be coming from some kind of environment or social expectations like that. I'm not talking about that here. I'm talking about, say, a US tech business environment that at least thinks it values speaking up with honest assessments.)
Ideally, management welcomes straight talk, and will do the right thing with it.
For example, if you've not been given reason to think the person above you is dishonest or unreasonable, and they haven't been given reason to think that about you, but you don't yet know them well, here's an example:
"The team is having some serious difficulty. Is now a good time to talk very candidly and constructively about that? ... Two things. First, I think that people are feeling that they don't have a good understanding of what the goals are, and how they're supposed to be prioritizing, on a daily basis. The other thing that seems to be bothering people is that onboarding is rough, and people immediately feel like they're not doing well, and then they aren't getting out of that feeling."
Note that this might sound a bit like some of the diplomatic framing of the article, in that it's not accusatory, but that's not what I'm doing. Some examples in the article attribute problems to the manager, and then use diplomacy, for cultural politeness, and/or to circumvent some pettiness they expect.
By contrast, in this example, I'm instead respecting the manager as someone who will take the information constructively. I'm also not presuming to attribute blame for the problems, since I don't have all the information about the situation, including not knowing everything the manager has been doing and why.