I think community source should be accessible and usable outside the community. A community license should have a provision for paid use by corporations. If Microsoft wants to use it that is fine - if they pay.
But if Microsoft wants to fork things, to me that is predatory. If I can't fork windows, why should they be able to fork community software? If they argue that people should pay for their products, it just seems fair to me that they should not get community products for free.
I guess the concept is playing by the same rules?