The ultra-ultra paranoid might use their popular and widely read blog - a blog which is almost certainly read by more than one or two people at the NSA - to post an enormous boat-load of misdirection that is nevertheless also helpful advice for people who are actually stuck attempting to secure Windows computers. Advice that happens to highlight what a nigh-impossible task that really is. (TEN rules? Good luck.)
I can't think of any reason for someone in Schneier's position to publicize his actual security arrangements at this time.
Then again, maybe he feels he has a duty, as a security expert, to use and thereby remain familiar with the most popular systems around.