LOL, yes, Microsoft has to provide all API and SDK to everybody. Microsoft has to allow Chrome browser on the Windows platform, no? Have you been out of the loop for the past 10 years on all of these things? But this has nothing to do with this case as Microsoft is not asking Google to provide API or SDK. Let me put it this way. If Microsoft does the same thing to Android phone (like no access to exchange), is it an antitrust issue? If Facebook comes out with a Facebook phone and denies all access to Facebook to Android user, do you feel the same way? If this disease spreads to every company, what do you say about this balkanization? The web is not built to be like this. I hope you see your partisan way.
I have zero problems with one company denying access to its services, software, sdks, source code to other companies, or their products. Facebook can close off any/all platforms they choose from accessing their servers and information, this would not bother me in the least. If that was a service I used, I would look elsewhere for services.
Having used linux for years, I'm very accustomed to this kind of stonewalling, and shopped for brands/softwares/services that provided me with access, as needed. Sometimes, this meant using a different os for very specific tasks, via emulation.
My (very limited, possibly wrong) understanding is that limiting access to all -except- ones own platform is where antitrust comes in.
This looks to me to be a very lucrative market (a gift from google?) someone could exploit on the wp platform.... maybe it will happen ?