Having also worked with end-users, I suspect the result of that study from IBM is due to how the users that push to get a Mac tend to be more advanced end-users than your average corporate drone - big companies love to standardize and that means everybody gets the same (with the notable exception of upper management) which is almost invariably all Windows, so there's a huge bulk of "just proficient enough with computers to do their work" people using Windows.

That said, I can see you point for backend guys chosing Mac over Linux because of the integrating headaches they would otherwise have with closed source mandatory corporate tooling: I myself have in a professional environment a far lower threshold to spend time mucking around in the OS to get something I need working than I do at home.