I find this line from the greeting letter a bit odd, "It often feels like I'm back in school, as I spend a lot of my time learning about issues I'm passionate about." Didn't he drop out of college to start MS presumably because he felt like the things he was learning in school were a waste of his time?
There's no conflict there. In an actual school, you're not the one setting the curriculum. This involves a lowest common denominator of a variety of subjects, some of which you'll never apply. I imagine that now he's spending his time studying things he's interested in and likely directly related to things he's doing or trying to accomplish.
I don't think that's accurate - from interviews, speeches and his own writings, he's always sounded complimentary towards his Harvard experiences; it's just that starting Micro-Soft was the right opportunity at the right time, and he grabbed it.