Racism is ignorance at it's most basic form (fear/hate what you don't know). But stereotype jokes, especially off-color ones can be some of the funniest ever, whether they are race, sex, age, geographics, etc. That's why they never seem to die off.
(Posted from the trailer, in the trailer park, next to 3 cars that don't run, in my wife-beater tshirt and mullet, drinking a case of PBR, 4 dirty children playing with trash in the dirt, playing an AM radio with coat hangar antennae, with my 17 year old wife I met on Jerry Springer when she was 15.)