Who asked them? And who audits that software? And what happens to Microsoft if some "bug" messes with the results? Hundred million dollar lawsuit by the party, I would hope, yes?
People should be outraged about this "Microsoft generosity". They're letting a private company put itself in the middle of the election process.
First off, election software should be open source. Period. If Microsoft is offering it "for free" anyway, why hasn't it made it open source? I mean, they are so generous and everything already!
Second, no private company should have access to that data or be able to influence that data in any way. If the party wants to offer the service online to see real-time results, then it should do that itself.
Third, the software should be audited by independent academic experts.
Anything less than these three points is an absolute outrage if you actually care about democracy.
