> Your employment agreement can include stuff like “if you say anything bad about us, even to your family in your own home, you owe us $50,000”.

Non-disparagement clauses are limited by the law, which in the United States is augmented by state-level restrictions. There have been some recent developments from the NRLB limiting how severance agreements can be attached to non-disparagement clauses, too.

So it's not generally true that you can be liable for $50K for saying anything bad about your employer in your own home.

The situation with this author is on the other end of "in your own home" spectrum: They went out and wrote a whole book against their employer that violates NDAs, too. Regardless of what you think about Meta or the author, this was clearly a calculated move on their part to draw out a lawsuit because it provides further press coverage and therefore book sales (just look at all the comments in this thread from people claiming they're motivated to go buy it it now). Whether the gamble pays off or not remains to be seen.

I think people living outside the US don't realize how few disputes here are actually allowed to use the official legal system when dealing with companies of non-trivial size. Many employment contracts, many service contracts, and even website terms of use require mandatory arbitration in lieu of pursuing one's claims in court.

And arbitrator companies (some of which are explicitly for-profit) know the hand that feeds them.

Ah, don't worry, we have a concept of "onerous clause doctrine" to help with that. Of course, it's almost entirely up to a judge's discretion what is and is not onerous, so...

Free speech on one hand, legal system capture on the other.

It's a condition of the severance payment. She didn't need to sign it. She wanted the money. Then she violated the terms of the contract.

> I guess I just don’t understand contracts and laws.

What's to understand? Person agrees to thing. Person is held to thing.