"Praise publicly. Criticize privately"

"Praise publicly. Criticize privately." It's an old saying with a great deal of wisdom behind it. If you think about it, it is very much about the golden rule. We all make mistakes. It's painful if those mistakes are publicly scrutinized.
I once worked under a manager who liked to post the last employee mistake on the wall. He would also copy many people in on emails that listed all corrections that were required on a project. He rarely praised underlings but criticized them daily. When pushback came, he was stymied. "I'm trying to help you," he insisted. But when he was publicly criticized, he was furious. I sometimes wonder if he ever learned why so many of his department left.
"Praise publicly. Criticize privately."
What's publicly?
Recently I was reminded that as soon as I tell a third person what I think, it's public.
In other words, if I tell you what I think about you or something I think you did; criticize you directly, it's private. If I tell no one else and you tell no one else, it's private. The minute either of us shares that, it's public. The two of us no longer control who knows.
If I criticize you and I tell no one else, I have kept it private. If you tell someone else, you have opened it up to public discourse. You may believe the person you told agrees with your side of things. Maybe they do. But will the next person they tell?
The things we say can have powerful effect. Words resonate. They are repeated and repeated. Once released to the universe, we have no control over their power or interpretation. As soon as we unleash a criticism of another, we have unleashed a powerful thing. Even if we believe strongly that we are right, it can have terrible consequences.
"Praise publicly. Criticize privately." And I would add, criticize carefully. Praise will return praise on you. Criticism will return criticism on you.