Here are my two cents:
Racist: Ulfric doesn't say that to the player but his supporters display that clearly. Adranne Avenicci is one of their victims. When Whiterun becomes a Stormcloak territory she said that she is doing less business than usual because the Stormcloaks don't like buying from anyone that isn't a Nord. And I don't care who and what a person is. If he/she is a racist then this person is not a hero in my book because I was not raised to hate those who are different.
Power Hungry: Ok, let's suppose Ulfric killed the king for another reason. Then the moot is summoned and the jarls choose another one who is not Ulfric. What would Ulfric do? Kill the next king or accept the decision? Hard to say.
Egomaniac: Hard to say too.
TES is not a culture, Ben. It's a world, a setting that contains cultures. So who's culture should I judge by? The Nords, who are of a completely divided mind during the game, anyway? The Dunmer? They have citizens in Skyrimm too. I should hand-wave and go along with cultures that espouse slavery or oppression? This is faulty logic, because it's a double edged sword. If we should be accepting every Nord custom at face value, than why shouldn't we accept the Imperial custom? Skyrim is a province of the Empire, subject to imperial law, so culturally, a good citizen would expect them to fall in line.
This "don't judge" argument holds as little water as the "Ulfric is a racist" argument. Plenty of Nords, fully immersed in Nordic culture, think Ulfric is a bad guy. So I guess he is because culture? See how that doesn't work?
I'm not so much surprised that people are saying that racism is okay in this game as I am with who is saying it.
You don't seem to understand what a race is. A dark skinned and light skinned Nord are not different races.
You also don't seem to understand what prejudice is. Treating someone as inferior because of how they are different, and excluding or oppressing them is prejudiced, not being able to tell the difference between race or species.
You have a good point when you said that real life racism would be a light skinned Nord that is prejudiced against a dark skinned Nord when they are both Nords and can do the same things. But what I don't understand is the problem the Nords of Skyrim have with other races. A Nord cannot breathe underwater and Argonian cannot withstand the cold, of course, but both can carry crates, however the Argonians working on Windhelm docks earn less pay than the Nords and the excuse Torbjorn Shatter-Shield is "Argonian's labor is only worth a tenth of a 'proper Nord worker'". Why? Just because the guy is an Argonian? As for Adranne Avenicci, why the Stormcloaks wouldn't buy her stuff? Because she is an Imperial? The Nords of Skyrim must learn that we can't judge a book by its cover. Khajiits may be criminals and drug dealers but that doesn't mean 100% of Khajiits are criminal scums. Ysolda knows this (she is a Nord, by the way) and she is learning caravan trade with a Khajiit to become one herself. Why those Nords can't treat all people, regardless of the race, skills and abilities, as equals? Those attitudes are unforgivable for me.