They each signed a "Separation Agreement and Mutual Release" on May 4th, 2001, that legally requires them to say the same thing. One pertinent section (of several) says this:
(c) Nondisparagement. The Parties also agree that they will not, either directly or indirectly, hereafter make any defamatory, negative or denigrating comments of any type or nature whatsoever about each other (or the other Party's employees, officers, agents, consultants, affiliates, investors or business partners) to anyone.
Robin