From what I've gathered, an uber is any pokemon whose base stats add up to +600. Pokemon whose base stats equal 600 are judged based on several factors.i know i sound like an idiot saying this, but whats an uber?
For example: Mew can learn every TM move: Uber. Manaphy can use rest during a rain dance and be completely healed and be awake thanks to hydration: Uber. Celebi has a horrible type combo and shallow move pool: Not uber
As for the uber argument, they are totally fair. Everyone has the chance to raise them as long as they are able to be obtained legitimitely. Didn't want to go to a Nintendo event to get a deoxys? Oh well. I didn't do that, but I don't complain when my foes whip out a FR deoxys.