For an open standard to take place: 

* All parties must agree on it.
* it must be free from royalty fees.
* It must be free from control of a single company.
AND
* it must be fully documented such that ANYONE can reproduce the implementation EXACTLY, simply by downloading the specs.

MS's OOXML is an open format by definition (although, even that's highly questionable). It is NOT, however, an open standard. A single company still controls the pace of it, and how it changes or develops. (What makes it worse, is that this company just happens to have a history of abusing its position in order to stay as the de-facto standard).

That's the difference between ODF and OOXML.

No one in the open source community is stupid enough to support someone who's being attacking them for a number of years now...Well, except maybe Novell and Miguel de Icaza. But that's another story for another day.