People consistently forget that large companies like Microsoft are made up of tens of thousands of people. There is a lot of new blood going into Microsoft every year. A lot of those new people "grew up" with Linux and FOSS in college. It is not even remotely surprising, nor unexpected, that Microsoft's stance towards Open standards and software would change over the years.
Even a lot of Linux nerds get hired in at Microsoft, because whatever your feelings are on the company, just their dev _interns_ make the equivalent of a $90,000k salary (if they were there for a year and not just 3 months) and student loans have to get paid off somehow, and hey once you start working there you realize that a lot of awesome people are there doing a lot of awesome things and the internal culture is fantastic and the company treats you well and why wouldn't you want to work there? :) (No, I do not work there and never have, but a majority of the tech people I know do; living in Redmond WA makes that almost unavoidable.)
Back on point, this initiative at Microsoft is just a sign of the increasing youth and modern tech-savvy at Microsoft, and the changes the company is going through after the huge internal company culture changes that happened almost a decade ago (when Gates left, his replacement in Ozzie did not have the same charisma with the internal techies, the company swelled its numbers of employees by a ridiculous number, and the company fractured -- for the better -- from a monolithic macro-organization to a colony of micro-organizations). To think that everything a company of that size does is all part of a secret hateful anti-everyone plot carried out by a tiny cabal of executives is, to be frank, outright freaking retarded. Big companies do not have a single brain. It's almost silly to even consider it a single company.
Some divisions are Microsoft are absolutely still run by anti-Open profit-mongering old-school jerks. Many others are run by much more Open-minded individuals these days. This new initiative exists because of those new people, not because of an evil plan by the dinosaurs.