Looks like this weekend is a Metric weekend. Blame my incredibly good taste in music. Enjoy!
There seems to be a lot of tension between the Forsaken and the rest of the Horde right now. How are Forsaken players aligned? Hardcore loyalists or servants of the Horde? I want to say the latter, but I can't decide considering how players are treated by Orc guards in UC.
This is actually something a lot of players have issues reconciling. Your player character is nearly always an exception of some kind -- the only one who could defeat _______, or an incredibly powerful example of X class, or the goblin who saved everyone's life, or the Gilnean that rescued their king. You're important in some way, or usually in multiple ways, by the time you hit max level. And you can even say that, personally, you're way different than others in your race or faction.
But WoW's narrative is hard-coded, and there's no room for your player character in it. Illidan was killed by Maiev and Akama. Varian Wrynn killed Onyxia. As important as you are, you're entirely invisible to the game's lore. It doesn't matter if you personally disagree with Sylvanas; as a Forsaken character, you don't get to choose to disagree with Sylvanas within the constraints of the game. The biggest act of rebellion you could take would be not to do quests for her or your race. But you're still a Forsaken.
If you're talking about Forsaken characters, as opposed to players, then I think from quests and dialogue it's pretty clear that the majority of Forsaken characters are loyal to Sylvanas and not to the Horde -- especially given that not even Sylvanas is loyal to the Horde.