User blog comment:Thedoucheinthenorth/A question of morality/@comment-5709731-20121215135055/@comment-5135631-20121215155630

Because the Empire is oppressing Skyrim, not leading it. Rightly or wrongly, the Stormcloaks believe the Empire betrayed their own principles in the war and as a result are no longer fit to lead Skyrim. Anyone can see the Empire is in decline, and the Stormcloaks want to leave a sinking ship.