Lots of people are saying this, but I don't understand it. My understanding (IANAL) is that when the CEO publishes something like this on the company's official web site, it becomes completely impossible for the company to win any future patent suits due to promissory estoppel.
Musk has effectively stuffed all of the company's patents into his office shredder. Good for him.
(Edit: He has also intentionally lowered the market value of the company by a certain amount, which is interesting.)