Have you seen these so called debates? Everything that even remotely says Ulfric is bad is countered by "You can't trust him, He's just a blacksmith, They are lying," From the most hardcoe SW supporters. Of course not all SW supporters are that hardcoe, and there are several that accept the faults. Just like I, as a Empire supporter accept the faults of that faction.
It is the hardcoe supporters of both Empire and SC that leave a bad taste when one comes to the forum.
Either way, like you said, no matter what the Thalmor win since both sides leave each other weaker.
But this topic is about racism! Not all Stormcloaks are racist, just like not all Empire supporters are not racist! It depends on the person.