[fjtorres]

Microsoft supported the Apple II with a CP/M card.
They supported Atari with their original product, MS Basic.
They sold Xenix at the same time they sold MS-DOS. They were actually the biggest *nix vendor on the planet in the 80's.
They were in at the creation of the Mac GUI and several Finder features were lifted from the Word for Mac beta.
When Lotus didn't do 1-2-3 for Mac, MS did Excel which didn't come to Windows for years.
They supported Atari again, with MS Write.
When IBM tried to break the clones with MicroChannel, Gates told Jobs to license Nubus and MacOS and offered to help.
In the 90's they were open to supporting Solaris (but MacNeally blanched at the minimum guarantee).
And all along they've supported the Mac with the best office Suite their coders can produce, even when the Mac version had features the Windows version lacked.

This whole Mac vs PC thing has always been more of a fanboy and media creation than anything of substance. (With a bit of Jobs product libel thrown in.)

MS has always been a tools and platforms company.
And they have always hedged their bets.

Money is money.

Besides, why bother being petty when there's room in the market for both?