Tango project aims to clean up the desktop

Uhh... "they're" not locking anything. "They" means who, exactly? The Tango people are not GNOME. There are some GNOME artists involved, but the lead person (Steven Garrity) is from Mozilla, not GNOME at all, and there are KDE and XFCE artists as well.

in fact Steven Garrity is very close to GNOME, just one example is Planet GNOME, where Steven is the person who created the template design.

And what if they were ditching oxygen for tango? So what? Would that stop you from replacing the icons with something else you preferred?

The tango project would then give you more flexibility to switch icons to your preference. Right now, when someone puts out an icon set on kde-look.org, I can't use it with Gnome unless I or someone else ports it to Gnome's icon spec. If all the desktops switch to the same naming spec, we won't have to waste effort making that icon set work on multiple desktops. Make it work for one, and it will thus work for them all.

Neither Gnome's defaults nor KDE's defaults has ever stopped me from switching to an icon set that I liked better. The tango project won't change that, it will just make it easier.

They absolutely are involved. The discussion linked to in the article was the XDG list, not the Tango list. The Tango list and the #tango IRC channel both have active participants from KDE.

As I have pointed out numerous times, the specs are the work of the Tango project, not the theme itself.

And only a child calls other people "fools" for not agreeing with their personal taste on aesthetics. You like the Playskool and Jolly-Ranchers look of the KDE themes? Good for you. That opinion does not entitle you to claim intellectual superiority over anyone else.

"Sorry, but you are stating something that might be misleading. KDE has exactly _no_ plans whatsoever for shipping the Tango icon theme itself."
That says nothing about whatever or not KDE people are involved.
But that's not what the Tango guys are saying, as pointed out in the other post. What I understood about Tango is that the specs are only the way to reach visual unification of all desktops. And that's exactly the reason why KDE and XFCE won't be "dancing"[1].
Tango is not just one thing--one of the goals AFAIK is to have portable icon themes, so that you can use your favorite in either desktop. Another is visual consistency, that does not automaticly mean to have one icon set, but rather to have a set of guidlines for third party application artists so that their icons look good in both desktops--this is why their style guidelines combine elements from current KDE and GNOME default icons (they probably bet on the fact that both styles are quite stable and won't expierence massive changes). If I comapre the guidelines to what is known about Oxygen I see that Tango style icons will fit in well--the styles are different, but not drasticly different (so the bet was sound). If Tango is successful I can well imagine that in the future desktops will derive their visual styles from it so that they can be have their distinctive look, but can still fit in with the rest of the free software world.

I personally find the theme-unification idea kind of pointless. A cluttered KDE application looks out of place even if it is perfectly GNOME-themed, because KDE does not have a (useful) HIG.

Also, it is impossible to create a perfect theme. Even WxGTK looks different from a standard GTK application. Just like a GTK themed Mozilla browser (XUL) looks fake.
And if you really care about the look of your desktop then you are not going to use apps from other desktops anyway.

Anyway, it never hurts to have a few more icon themes available.

Author here.

Actually, it's not. The project is the creation of the naming spec and the metaphor spec. The icon theme they are working with is just a test suite. When it is finished, it will at most be a reference implementation of their idea.

The naming spec and the metaphor spec are a framework designed to be used by other themers. It is "work towards unifying" in the sense that it will make the job of all themers easier; it is not itself an attempt to unify any themes.

Admittedly, they should be clearer about that distinction in the material on their wiki. But talk to any of the involved artists, and they are perfectly straightforward on the goals. It's a very important distinction if you are a themer or icon artist.

Right now, you have to make multiple theme "packages" for the different desktop environments. Their goal is to create a standard that allows the themer to create a package that all environments can agree on and will know what to do with. A theme adhering to that standard is a unifying theme; the standard itself is just a reference document.