While I can understand that the Empire had to sacrificed public worship of Talos in exchange for Survival the nords don't see it that way. They see it as being weak and that's why ex former legionaries like Galmar and Ulfric decided to create their own organization “The Stormcloaks” to retake back their freedom and make Skyrim independent from the wrath of a weakened empire. I'm sure Ulfric would've rather die fighting then to surrender to the Thalmor.
So what you're telling me is that the empire was so weak and so vulnerable that if they were to get attack again they're unable to defend themselves because they don't have the resources? Not good. Ulfric's Subordinates are not ignorant. Galmar made a good point when he said "The Empire is weak. That is why we fight them. Skyrim must be ruled by the strong." If the empire can't defend themselves then how are they able to defend other countries like Skyrim from the wrath of the Thalmor?
So yes, that's my point. They won't accept the facts, they just simply jump on Ulfric's bandwagon because it's mildly relevant at the time, and completely disregard WHY that stuff happened, and what the possible consequences will be for everyone - Ulfric's drones are taking the situation at face value, an army of brainless yet devoted thralls if you will. Starting the Civil War might've been a fair idea later, but given the circumstances doing it now makes no sense, and again, I don't think Ulfric is that moronic - I think he has his own selfish motivations, and those uneducated and short sighted Stormcloaks who follow him fell for it.
The Empire - Including it's province of Skyrim's army - Has been defeated momentarily by the Aldmeri Dominion. Everyone has been preparing for another grand conflict in a Tamriel based Cold War, so what does Ulfric do? Incites a rebellion and splits one of the Empires greatest provinces in half, weakening the Empire and more so Skyrim as a whole. Great job Ulfric! On the verge of another great war with the Aldmeri Dominion you decide to splinter one of Tamriel's best hopes, but again, I'm pretending he's smarter than that and is just power hungry. Lucky break for the Aldmeri Dominion.
Also the Empire isn't supposed to defend Skyrim with just Imperials. A good portion of the Empires troops are in fact, Nords of Skyrim. No matter what way you cut the butter here, starting the liberation of Skyrim was short sighted, selfish, and incredibly stupid. Yes, Skyrim may deserve to be it's own sovereign nation, but that's not in anyone's best interest right now. Except for Ulfric, who would be crowned as high king of course.