His mental illness is, he always wants to devalue others
You can't base psychological diagnostics on forum posts. And by calling it "mental illness", you're doing exactly what you accuse him of: devaluing him.
I think I am in a very small group that would like to see more negative feedback and less neutral.
As long as it's for the right reasons, that's okay. But if it's for the wrong reason, it reduces the warning potential of negative feedback by making it too common.
I really thing nobody reads the neutral.
I
sometimes use neutral feedback to stand out.