The link you posted was published in February a good two months before the IE 11 rumours started, so I'd hardly call it an example of a change of heart.
On checking, neither the Windows Phone nor Windows Store has a non-compete clause on browser tech (unlike the iOS 2.17: Apps that browse the web must use the iOS WebKit framework and WebKit Javascript); so do not prevent a non MS browser being developed which could allow people to use WebGL on these platforms. (runtime compilation and signing of shaders aside)
It is an example of how to use the native Direct3d of the platforms, which may be helpful to people developing WebGL tech (Chrome and Firefox translate WebGL to DirectX using Angle on Windows)
For widely available tools Microsoft provide a free version of Visual Studio (Express) and provide a full MSDN subscription for every Microsoft product for free to start-ups for 3 years via the Bizspark program. MS have is open sourced .NET via Mono and you can develop cross platform (Win/Linux) DirectX using the open source Axiom 3D built on Mono.
I would like nothing more that IE to support WebGL, as I do believe WebGL is the future and I'd like greater support faster, but please only assign blame where blame is due; it is not constructive.