But it was a severance agreement. She accepted a sum of money for agreeing to not disparage. You don't see anything wrong with someone knowingly accepting these funds, and then turning around and immediately violating the agreement by writing a book (making even more money in the process)?

If it's about whistleblowing and doing the right thing, why not just refuse the money?

There should be a statute of limitations on this stuff. Otherwise we’ll see things like chemical plant employees who signed such an agreement keeping stories of dumping to their deathbeds.