Microsoft: no way to support WebGL and meet our security needs
Three main concerns are enumerated in the post: WebGL exposes too much sensitive, privileged, or unhardened code to the Web; depends too heavily on third-party code for security; and is too susceptible to denial of service attacks. The first of these is perhaps most significant. Video hardware and video drivers are traditionally only exposed to relatively "trusted" code—programs that the user has explicitly chosen to install. Display drivers are notoriously unstable and buggy, and developers of 3D software have to go to quite some effort to ensure their programs do not use (or misuse) the 3D hardware in such a way as to cause problems.
more on arstechnica.com
Microsoft refuses to implement WebGL, giving security as a reason. Interestingly, it's not an issue for every other browser out there and even for Microsoft's very own Silverlight... It's worth to read response of the VP of Technology at Mozilla, Mike Shaver.
