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…
I agree with you that's how it should be, but experience tells me that everyone is insecure and it's hardly correlated with position and job security. People lower down the chain are insecure because they could legitimately be let go at any time for any reason. People higher up the chain are insecure because any loss of face is debilitating. Especially having failings pointed out by someone "below" them.
You don't do it in public. There's no face to lose in private (you're a subordinate, face is only lost among peers and superiors).
It is, however, not really a good idea to be 100% blunt out of the gate. There's a dance to it. But in public, I'm there to make my manager look good, and in private I'll tell them exactly what I think. Once they're confident I'm there to be at their back, it's never gone wrong, even in highly disfunctional orgs (I'm a consultant and get brought in to play "doctor" with hopeless projects a lot).