Microsoft doesn't have a history of patent lawsuit trolling. To the degree that Microsoft does seek software patents it is generally as a matter of defense against other large corporations.

I think the possibility that MS might be trying to do the right thing here, for everybody not just themselves, is reasonably high and shouldn't be dismissed. At the end of the day MS is a developer centric company, they pride themselves on the ability to make things, and patents are an annoying side show to that.