So do him a favour and delete the copy. Out of respect to a great writer.
The bit that I don't get: Even if Steve's release was accidental, if you write something like this even when it is for internal use only, you can still count on it being reposted in a public place. 'All of google' is a large number of people, all it takes is one copy and the genie will never go back in to the bottle.
If you want to keep something to yourself don't store it on a company website or write it out in an email.
Company confidential typically translates into 'delayed, uncontrolled publication' or 'evidence to be used against you' depending on the circumstances.
If you can't stand by your statements in full view then you probably shouldn't make them to 10K+ people, especially not when you're a well noted blogger.
Especially one where he pretty much writes that Google's #1 is not 'Steve Jobs'.
Really, I think that no matter what that this would have found its way to the general public somehow. That said, I think it's great that he speaks his mind like this, even if it is intended for an internal audience only.