Honestly, I think that they got the green from Bush and His Evil Minions™, or at least Dick Cheney before cluster bombing cities, but cluster bomb cities they did, and they did it before the Russians moved in.
Even without consideration as to right or wrong, it would be catestrophically stupid to allow Georgia into NATO for one simple reason: It will give the Russian FSB unprecedented access to NATO secrets, because the Russians have completely penetrated the Georgian state security apparatus.
That’s why the Russians were able to launch a devastating counter attack: they knew that it was coming, to the minute and individual battalion level battle plans, and so could respond quickly.