Warhammer is indeed a World of Jerkass. The Bretonnians are jerks towards their peasantry, their "noble knights" only acting such whenever a strong enough king has them on a tight enough leash. The High Elves are jerks towards everyone because they believe they're the only ones who can properly counter Chaos. The Wood Elves are jerks towards everyone because they think they might destroy their home forest. The Dark Elves are jerks because they get off on it. The Dwarves are jerks because they've lost most of their kingdom and consider everything every other race makes complete and utter gobshite. Chaos consists of four jerk gods and all their jerk followers. Beastmen are jerks because they don't like civilization. The Skaven have "backstabbing jerk" as their racial hat.
The only race that doesn't consist of complete assholes is the Empire, and even they are no saints, what with their whole cult of witch hunters.
I personally prefer the delicate balance that Warhammer does have with its High Elves. Their fluff is generally spent 50-50 between being arrogant, hubristic and dickish, and being proud, decent and fair, so that they kind of balance the two things, creating a sort of "elves vary as much as people do" atmosphere that I do enjoy.