Originally Posted by
Kyphael
Undead turned into traitors and scumbags*
Fixed the title for you, OP. Baine and his Tauren have more rightful claim to the Horde than Sylvanas and her Undead. The Undead were allowed in the Horde by Thrall as courtesy, if anything to be used against meat shields against The Lich King; The Forsaken needed the Horde more than the Horde needed them. Vol'jin making her Warchief was a mistake that the founding races of the Horde will soon rectify.
The Alliance vs. Horde conflict does not define the Horde in lore. Maybe in-game, but in lore, a noble Horde character finding his "Warchief's" morally ambiguous does not a traitor make. What is defined as game play ideology does not define lore. Warchiefs have been challenged and overthrown before. Sylvanas won't be the first and given Blizzard's creative reach, she won't be the last.
As for Lor'themar's reasoning, he's perfectly within his right to do what he wishes in the best interests of his people. He's not Sylvanas' underling like Nathanos, he's a racial leader, regent to the throne and commander of the forces of Quel'telas.