The most common misconception I've seen recently is people assuming that everyone or everything that is in league with the Old Gods is being controlled. You don't have to be mind controlled to work with them.. most of their minions aren't forcibly controlled.
I'm pretty sure Deathwing was the most controlled out of all of them. He basically HAD to listen to them for over ten thousand years due to his "gift" which drove the poor guy to insanity enough to plop himself on the Wyrmrest Temple in an alternate possible future.