> I've worked with people who had a master's degree in CS who couldn't code their way out of a wet paper bag.

"Programming" consists of an insanely large number of isolated communities. Assuming the respective person is capable, I would assume that he simply comes from a very different "programming culture".

I actually observe a very related phenomenon for myself: the more I learn about some very complicated programming topics, the more "alien" I actually (start to) become to the programming topics that I have to do at work.