WebGL is NOT a W3C standard.
Its Khrnonos standard and they work in a way that 3D industry approve. So WebGL is standard. Anyone could join to create it, anyone could voice their opinion about it. It have open and free conformance test (just like one for JS), its proven to be working on any GPU with programmable shader pipeline (including one hiden behind DX).
“Direct access to hardware” only boild down to ability to preform Denial of Service, and even that can be easily prevented by GPU vendors and OS vendors if they want, and those who support WebGL eg. every one, wants.
“All non-Win8″
Lie.
AMD customers even on WinXP are secure! AMD have code that prevent DoS..
Win8 have new GPU drivers model that guarantee safety.
Linux is secure also.
Do not know about OSX.
Have not seen or heard any toubles on Android.
So BIG FAT Lie here.