The fact that they wrote up half-assed incomplete documentation of it and submitted it to the W3C for consideration as a standard doesn't change that. It's actually more or less like OOXML except it hasn't had the feedback-and-rubberstamp process happen yet. With any luck, that process won't happen, in fact (in that there will be actual discussion and actual specification, not rubberstamping).
Now if the CSS working group actually starts actively working on 3D transforms (hasn't happened yet) and anyone other than Webkit actually implements them, then we can talk about them being something other than what they are now.
There _is_ a bit of confusion here because vendor prefixes are used for both experimental implementations of CSS working group proposals and totally random proprietary gunk. The problem is telling the two apart... ;)