At the begining of wotlk, the lich kings forces attacked both faction's main capitals (org and SW), so then the alli and horde kinda "teamed up" to kill the lich king. They weren't really friends but acted less hostile towards each other. Then Wrathgate happend and we went back to completley hating each other. So now we should be teaming up again to kill deathwing but instead there is more hostility between us then ever before. What is the reasoning behind it?