Plus the power imbalance.
And the non-disparagement wasnt in her hire agreement, it was in her severance agreement, in exchange for a negotiated amount of money. Author was wealthy enough to afford dedicated lawyers to review.
Furthermore, this was a severance agreement, not employment agreement, so having a lawyer review your contract is not going to delay you from starting your role.
I have my issues with this situation, but "they might not have read/understood the contract" isn't one of them.
I don't think we can hold people responsible for these types of contracts if they are under duress, for instance, under threat of the loss of their job. In this case the person signed in order to get the promised severance package, without which they wouldn't be able to continue with life-saving medical coverage, in my opinion that would also be under duress.
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.