The Stormcloaks openly engage the Thalmor whenever they encounter them.
In Skyrim.
"Out of the public eye"? Oh, that's sure good to know. 
Yes, because of the peace treaty. Are you not following?
Blaming the Victim 101. If you're not grotesquely ignorant about what went on around Markarth in the aftermath of the war, you know that the Stormcloaks only exist because that condition was being enforced. You cannot claim them to be the aggressors in this conflict; their actions are primarily defensive, taken to preserve their homeland and way of life. The Thalmor are in Skyrim now because the Imperials permit them to be there - do you seriously deny this?
They are the aggressors because they were the ones declaring the war against the Empire, and Skyrim isn't their homeland to preserve - it's been a part of the Empire for ages. And need I remind you that it was originally the Nords who drove the Aldmer out their homeland? You could even say that the Thalmor rightfully want their land back - which is exactly what the Stormcloaks are arguing for, as well. Except that the Aldmer are the original residents of Skyrim, not the Nords. I don't personally support Thalmor motives, but I might ask you anyway, why is it that you believe the Nords are any more deserving of Skyrim than the Aldmer?
And yes, the Empire let Thalmor in Skyrim because denying them would be denying peace. That wouldn't even have been a problem if not for Ulfric's actions.
Except the Imperials allow the Thalmor to traipse through their territory, freely torturing and executing citizens at whim. Say what you will about Jarl Ulfric, but he doesn't tolerate that.
He does seem to tolerate the oppression of non-Nord races.
Oh, right...I almost forgot about that big, impressive war the Empire is conducting expertly "behind the scenes". 
Once again, you fail to grasp the concept of
temporary peace conditions. Yes, the Empire will inevitably fight the Thalmor, but for now they settle for guerrilla warfare.
Right, the Stormcloaks prefer war to slavery and always will. I would agree that is indeed the main difference between them and the Empire.
Right - I guess not granting the same basic rights to other races isn't slavery. And how exactly are the Empire slaving Nords, again?
You've managed to fulfill Godwin's Law and Hitler isn't even a part of the same canon. Well done.
Pulling the Godwin's Law card isn't any better than pulling the Hitler card, especially when the allusions drawn to the Nazi regime are legitimate.
I don't happen to believe that fighting to preserve the rights of your fellow countrymen against a thoroughly corrupt and oppressive foreign authority is a "shit idea". That is where you and I differ.
That's funny, I think so as well. Except that in our case, the Stormcloaks are the corrupt and oppressive authority. Not sure why you would even bring that up, considering you support the Stormcloaks.