I suppose think about it like you’re the captain of a ship. Imagine a captain always complaining about their peers, the ship, their outfit etc. And when giving orders they sound out their whole thinking process about why they are doing x or y. Versus never complaining or explaining in public. Certainly the former would be a less inspiring and weaker leader.

Maybe a more contemporary aphorism is "don't let them see you sweat." Not identical, but seems similar enough.

This article just follows its own stated principle

And yet, I feel so validated as a commoner who has (mostly in US politics) felt as though all rational rules of conversation, question and answer, and accountability are suspended.

Naive me joined other commoners to express aghast surprise at how stupid and clueless our leaders were (are!), completely clueless to the idea that perhaps we were (are!) being managed and that our rage burns off energy in a mostly harmless manner.