From what evidence do you draw this conclusion? I'm not trying to be sarcastic or flippant, but genuinely curious, I've heard other people make such statements about Ulfric and the Stormcloaks and I'm honestly just not seeing it.
I can't remember the names, I'm horrible with names. But overheard conversations, Ulfric and that Man-Bear-Pig advisor of his. There is also a book somewhere I read (I tend to read many of the books all the way through) that was written by either a Stormcloak, or a Stormcloak sympathizer. The book isn't just racist, its flat out hostile to everything not Nord. I find the Talos thing a really poor excuse for armed insurrection, as it was very poorly enforced. Hell, Leggate Rikke, who you work for for the entirety of the civil war quest, is a Talos worshipper. A Leggate isn't some random officer, that's a high ranking person.
Ulfric not only allows Dunmer to only live in the Slums, and Argonians are barely allowed off the boat, but he turns a blind eye to open racial antigonizers roaming his streets. That [censored] isn't exactly subtle about what he does at night. This is happening in HIS city, not some province that's far away and really not at the foremost of his thoughts, its his front yard. The mid 30s Germans Ghettos... I mean gray quarter... I wonder, do those Dunmer get to mow lawns and pick apples?
And then there is Kristallnacht... I mean High King Torryggs assassination. From what I've been able to gleen from the game, that was an out and out murder of a friend for political power. Seriously, the battle-hardened Ulfric endowed with The Voice, challenging Torrygg officially was the furthest thing from fair. He didn't even talk to his friend before challenging him to a fight to the death he had absolutely zero question about winning, and then using a Shout to start it off. Shouting a friend to death because you want the chair he's sitting on.
Pile all of that on top of the Talos worship thing the Stormcloaks are in a tizzy about. Who was Talos? That's right, the first Septim, the creator of the Empire. The Empire the Stormcloaks are seeking to destroy. The Stormcloaks, pissed about not being allowed to worship Talos, so they actively seek to destroy the only thing left in existance that was formed by Talos's very hands, The Empirej.
Then there is the dossier on Ulfric. He was a Thalmor asset, it says so right there in game lore. It is damning evidence against the guy. Makes me wonder just how much of a Talos guy he really is. Personally, I believe he is using the Talos grievance the real people of the Stormcloaks rally under to provide himself a rabidly loyal core. He was captured by the Dominion, interrogated, and then led to believe information gained during his interrogation lead to the fall of the Imperial City. After all of this, contact was made with him after the war and he proved his worth. That can only mean that he actively pursued Dominion goals.
As for those that say the Empire capitulated to the Aldmeri while they were winning. Um, hello? Did they not listen to the NPC's during the main quest. Skyruler Temple was taken and ransacked by the Dominion, the Aldmeri sieged and successfully took the Imperial City. That doesn't sound like the Empire on the winning side of anything.
I do not hate the Stormcloaks, not at all. My main in TES games is always a Skyrim Nord. The Empire was created by one of Skyrims greatest, and the Nords are the backbone of the Imperial Legion. My mains always feel that the Empire must always come first, Septims creation must endure. While my Nord's heart goes out to the Talos faithful in the Stormcloaks, the Empire must not be allowed to fade into history.