The fact they have office on Android, iOS, and osx proves it's about market share and common sense, not some fabricated hatred or fear of Linux on the desktop.
Well, the same argument could be applied to their open source contributions. Considering that [canonical corporate view is that] patented ideas are expensive to produce, and that exFAT is patented, what's the financial justication for open sourcing it (the specs or else)?
The argument is ultimately against "Windows love Linux". The thesis of the parent is just that they're doing unsubstantial moves (or worse, manipulative ones), and that if they "truly loved Linux", they would do something substantial, which, for the corporate world, is to support Office on Linux.
As for MS's contribution to open source you have to consider the difference in magnitude between the revenue that Office generates and the revenue that their other open source contributions do (would?). Then consider also the development effort involved.
It looks like OP just wants exactly what MS doesn't offer completely disregarding the alternatives, and I'm pretty sure they would not be willing to pay the markup for the extra development involved.
Do you have a source for this hyperbole??