In a better world, disparagement would not legally refer to the dissemination of factual accounts.
In such a world it would only add to penalties for proven libel.
It’s a pretty simple concept: if the truth hurts, you’ve got no one but yourself to blame.
NDAs theoretically should never be able to paper over illegal actions. In a similar vein, non disparagement clauses should not be able to paper over the publication of legitimate insider experience of terrible — even if legal — behavior.