I wonder if this ritual of meta-self-policing serves some particular purpose or if it's just a case of the brain drawing comfort from going through a familiar ritual. "This comment adds nothing" is like the reverse amen in church of our days.
The purpose was to discourage comments which added nothing I thought.
Another example of context collapse. Meta-meta commenting always adds something if only unironically.
I think it's just people who can't help but tell others how to live their lives.
The GP comment adds social pressure so useless comments are less likely to be made.
I'm sure you believe that works.
If you don't believe it works, why make that comment?