To be sure we'll need to see the order that the lines are actually spoken in game.
If he complains about human bigotry and THEN gives the 'old alliances' line in game, I'd say he's either speaking of some mystery group, or far more likely thinking of breaking off from the Horde as Vol'jin once did.
If he sais the 'old alliances' line, THEN the Dalaran incident happens, then he goes on his bigotry spiel, then I'd say he was referring to the Alliance but Jaina's actions have made that impossible. I think this fits well with his line that she's 'pushing them closer to Hellscream's Horde." My personal theory is that he was considering switching sides because of Garrosh but Jaina has forced his hand and cut off that possibility. But we won't know for sure until we play the quests or scenario these lines are spoken in.