Someone once aptly described to me how Microsoft handles standards as "they take a normal, rational standard that everyone agrees upon, then they screw it up just enough that only their products will work with it."
To be fair- GMail doesn't display background colors either.
As long as they're sending the e-mail to someone who also has Outlook and who isn't using the Outlook Web Access on their exchange server :)
Seriously though Microsoft's obviously trying to shift the issue to Outlook's use of Word when really the issue is how bad their Word engine renders HTML (though I do think "fixoutlook.org" picked the very worst example for their comparison). It's a good way to win an argument but a bad way to take product suggestions.