"Secret patches are neither new or rare. "This has been going on for many years and the action in and of itself is not a huge conspiracy," said Andrew Storms, director of security operations at nCircle Security."
What is unusual is that Core took Microsoft's silent updates public.
Not that this should go on anyway, but don't go thinking this is a rare instance and they are stealing your milk money, it happens enough to be of some sort a standard business practice.
Adding features does not necessarily increase functionality -- it just makes the manuals thicker.