Half of the Nords in Skyrim disagree with you. All those lives lost just so the Empire could sign the WGC disagree with you. Not to mention High King Istlad, a true Nord (according to Ulfric) who approved the WGC.
They all collectively put the Empire first.
Ulfric put the Empire first.. Until the Empire put everybody else LAST. And like I said before, you're wrong about half of the Nords disagreeing. Visit every hold in Skyrim, talk to the NORDIC citizens then come back here
How's that funny?
No, Ulfric has emotional issues and seeks what he thinks
he deserves. Skyrim is NOT just made up of Nordic citizens. The Legion is full of Nords and the country including Whiterun favors Empire politically. So it's actually more than half of the population is for the Empire.
So, why don't you leave Windhelm for a while, step outside your comfort zone, and try to listen to others who don't agree with everything Ulfric tells you.