Yeah it doesnt make much sense to me either, but i think what they mean is they want to make the association that you MUST use Windows and IE10 to run HTML5 apps, which obviously, is ridiculous.
I assume they also want to add "features" onto HTML5 too, in a similar fashion to ActiveX.
Its just the way Microsoft think, they have a very proprietary mindset, IMO.
Because those extensions are typically used to provide functionality that is intended for eventual inclusion in the CSS spec.
One would expect "Microsoft adding features to HTML5" to involve something other than participating in the cooperative advancement of a nice universal standard.
I assume they also want to add "features" onto HTML5 too, in a similar fashion to ActiveX.
Its just the way Microsoft think, they have a very proprietary mindset, IMO.