Regardless of how some people in the free and open source software community feel about software patents, we all understand that it is the legal system we have in place.  We all understand changing the system is a different discussion.  The community deeply respects intellectual property.  The entire free and open source licensing space is based on strong IP law.  People want to fix infringed claims.  But we can't fix what you won't share.

Choose one (and explain)

a: We want to fight it
b: We want to minimize the impact on our business
c: We want to leverage it when possible (explain how)
d: Heck, we'll even be an open source company one day

Microsoft has a wealth of software assets that are not products.  So take the discussion of "not a business model we can embrace" off the table.  Microsoft has been "studying" open source and "learning" from open source for almost a decade.  No one is suggesting the release of the Windows or Office software bases.  Why have so few experiments been done?  Quit publishing licenses and start publishing software.  

What would the implications be for IP in the broader world, if the "proprietary" software industry were to capitulate wholesale to the demands of the free software movement?

Microsoft is giving this away freely, Microsoft is attempting to build a community around it, Microsoft is attempting through it to establish itself as a player in the formerly despised Hobbyist marketplace.

All of which suggests that Microsoft may well be attempting to do this on the cheap, on the understanding that Hobbyists do not care about quality - which is of course a load of bovine excrement - Hobbyists do care quite a lot about quality.

Sam Ramji claimed last year that Microsoft only uses its patents defensively. Many companies have licensed their patents to the open source community without restrictions. Is Microsoft making so much money from patent licensing that it doesn't want to license them to the broader open source community without commercial restrictions?

Regardless of the correctness of the patents you claim around Linux, the sabre rattling that Linux infringes without action looks cheap and untrustworthy. Was it worth the lost trust and reputation in the broader development and partner community? How do you know?