under Liadrin, who is Horde. And you already see high elves visiting Silvermoon back in Wotlk, doesnt make Blood elves neutral at all.you're ignoring the basis for elven reunification (which is desired)
Lol the established lore has them farther into the Horde than ever before. Keep dreaming about them being neutral. That shit ended in Burning Crusade.the established lore, the benefits to the race's withdrawal from the faction conflict, and the potential improvement to game play.