And you thought the Microsoft/open source divide was political...
Mac people and Windows people seem to have more mutual scorn than open source and Windows people have for each other. Just one more reason to believe that open source is an opportunity for Microsoft, not a threat.
Macs and Windows are separate entities, though virtualization is changing that. Open source and Microsoft need not be.
All that said, I do think we need to remove the political and/or religious vitriol from the discussion.