A) Created a rebellion faction to seize control of Skyrim from the shackles of a dying empire.Slayed the High King in an attempt to usurp the Throne of Skyrim He wants to be High King, whats wrong with that? The previous king proved that he was weak, and unable to defend himself in battle so why does this make Ulfric into a bad guy?
B) Fighting for independence from the empire.Unilaterally plunged Skyrim into a possibly unnecessary bloody civil war that irrefutably harms the population and resources of Skyrim. And the empire had nothing to do with this war that Ulfric created? Nah It couldn't be it. Ulfric is some mad tyrant that gets off by watching his fellow nords fight each other to the death, right? This war was created BECAUSE OF THE EMPIREs decision to ban the worship of talos. Ulfric couldn't watch his homeland get invaded by the Thalmor, which technically it is because they're snatching up people from the streets and from their homes, and imprisoning them or worst slaughtering them right then and there.
C) Fighting to restore the worship of Talos in Skyrim.Forced the Empire to actually enforce a previously toothless edict against the worship of Talos and enabled the Thalmor to seize, interrogate and torture the people of Skyrim. The empire gave in to the Thalmor by signing the treaty. Then Ulfric, the only man with courage, realized how dangerous the situation was, step up to the plate and told the empire and to their elven masters to take a hick.
D) Fighting to make Skyrim strong again by wanting to be High King.Fighting to make both the Empire and Skyrim weaker to fulfill his own narcissistic ambitions. You are wrong in so many ways, but you're free to voice your OPINION.
He's the only Jarl who actively assisted the Dovahkiin in stopping Alduin which saves not only all the people of Skyrim but of Tamriel as well.