Why are we even surprised Microsoft is only half-assing their GPL'd virtualization drivers for Linux?
After all, the ONLY reason we got them opened in the first place was someone busted them for violating the GPL in the first place, and they were never interested in releasing real FOSS anything in the first place. How they got the OSI approval for one of their licenses is a mystery to me. I would have rejected it outright simply on grounds of principle. Here we have a company that has internally and publicly declared FOSS its enemy, after all.
Thus, I don't feel warm fuzzies when Microsoft does stuff like release GPL drivers, establish an "open" source license, supports projects like Mono or Moonlight, or opens sites like CodePlex. Their history is enough, in fact, for me to stand back and look for the ulterior motive and wonder when Microsoft is going to pull the rug out from under and screw those gullible folks who actually think Microsoft turned over a new leaf purely for the reasons stated above. I'm too familiar with their history for me to think they've actually changed, especially when their faux-friendly behavior towards FOSS doesn't look like a change from any other case of EEE or "partner and screw," two of Microsoft's favorite tactics.