The set of states with vetos may be a little out of date - it's basically the major powers left standing after WWII - but the principle is still useful.
I'd call that a contradiction. The principle can't possibly be that useful if, a few decades later, the result of its application is deadlock.
Anyway, I'm not suggesting they should. It just crossed my mind as something they might look at after this.
It deadlocked less than a decade in, which is a big part of how we ended up with the current operation where the things in the UN Charter that plainly say they require the approval of all the permanent members of the Security Council are treated as if the permanent members have a veto which they must be present and affirmatively choose to use. (It's also how we ended up with the "Uniting for Peace" [1] framework for an end-run around deadlocked veto powers even if they are present and actively voting.)
[1] http://en.wikipedia.org/wiki/United_Nations_General_Assembly...
The UN isn't NATO -- the whole point of it is to have a common forum for countries that aren't military allies and have conflicting interests.
EDIT: Just a general assembly vote was enough, apparently. That's a weird situation all around though, hard to analogize to kicking a country off (as opposed to deciding who speaks for that country).
It takes a 2/3 vote in the GA to expel a country completely from the UN. (See Articles 6 and 18 of the Charter.)