Well from a business perspective, during his tenure he tried to capitalise on MS’ dominant position on desktop and server in order to promote dominance on the emerging mobile-client platform. This he or the company he presided upon failed to do, and he retired after the “screw up”.
But that does not mean that he must continue dumbly advocating that there be strict adherence to what he tried, and failed, to do. After all, consistency is only a value if you are not a screw-up.
He continues to be MS’ largest single investor. That gives him a large vested interest in advocating that it behave rationally, even when rationality in this sub-game is at odds with the strategy he pursued previously.
Ideally MS would have succeeded in perpetuating its dominance to the new platform. It did not, so now it’s the case to do something else which is at cross-purposes with what would have formerly been ideal. This is not evidence of fallacious thinking; much the contrary.