Any Stormcloak is racist.
Hey, what if let's say us Norwegians just one day grew so powerful and took over your dear USA. We would change the rules and you wouldn't be happy (Ofc you would be happy, but...this is an example). Wouldn't you want to have at least some control over your own country? Wouldn't you fight against the Norwegians/"Imperials", because you wanted your America back? Oh, you would?? RACIST!!
Just think for a second, most Stormcloaks aren't racist, just as most people in this world aren't racists either (right....?). Most of the Stormcloaks just fight for their country and want their Skyrim back.