Official WoW Expansion Talent Information
Well, the leader of the scourge is a human ex-paladin, that would be prince Arthen, who killed his own father. The necromancers that propped up the scourge were humans. The scarlet crusade willfully work for the burning legion just because they hate the undead.
I also don't understand the knock against the orcs. They were dominated by a far superior enemy and used as pawns in the outlands. Finally thanks to Thrall they broke free and the PCs that you make in WoW are part of those "good" orcs. Yeah so the Darskpear Trolls used to be cannibals, I guess you don't have to trade fine cuisine tips with them.