What about "earnest, blunt, non-sugar-coated feedback" that is useless, uninformed, and counterproductive to researchers? I was under the impression that that was the concern here.

Just because someone says something non-sugar-coated doesn't mean it has any truth or value to it. In my experience, a lot of the people who publicly congratulate themselves on never pulling any punches and telling it like it is and keeping it real, etc., aren't motivated because they feel like they have valuable feedback to offer (they usually don't), but rather it's just a way to act out and maintain a tough-guy public persona that they want everyone to believe in.

I'm 100% in favor of public peer review, I just question the value of stereotypical Linus Torvalds-style "I'm just telling it like it is, you idiot" feedback that some people fetishize in these parts. The best course of action here is by definition whatever leads to more and better research, with whatever the appropriate amount of public and private peer review is that leads to that outcome.