A good reminder not to sign contracts with non-disparagement clauses, if you can help it. Seems like good territory for California to ban like they did with non-competes. At the very least they should be restricted from inclusion in severance agreements - at that point the company already has you over a barrel.
I mean, a reasonable non-disparagement clause for your current employees makes sense. You don't want your employees actively undermining the company in public. If they don't believe in what you're doing, they should be able to quit and say whatever they want. It should end immediately when your employment ends. It should be illegal to make it compulsary for severance packages, as many companies do.
And there need to be serious regulations about how these agreements can be used, and those regulations should protect whistleblowers at all costs. Like a public figure suing for libel/slander/defamation, the burden of proving statements false should rest entirely with the company.
I'm not sure we can hold individuals responsible for signing these non-disparagement clauses. They often don't have a lawyer to review the paperwork and, I am sure, employers like Facebook aren't going to wait for a new hire to have a lawyer review that paperwork. There's a real pressure to sign everything with HR and get on to starting your new role.
Plus the power imbalance.