Really? That surprises me. Loads of people at MS have MacBooks - apart from anything else, websites and software that Microsoft makes needs to be tested on them. I also know several MS FTEs who primarily use Macs at home. Sure they probably take minor digs at each other for it, but MS doesn't force you to use Windows. Use the best tool for the job.
Yep your right, this was quite a few years back though and in the UK campus.