Native American Stereotypes

So today I am writing an essay in English on Native American stereotypes in the present media. Sure there are a lot of them: the noble Indian, the ignoble Indian you see in all the westerns who is always stealing the beautiful girl, the casino Indian you see in all the current comedies, and the squaw.

Looking into all of these things got me thinking is there really more native American stereoypes then causcasian stereotype? If not why are the minority stereotypes so much worse then stereotypes we portray on our own race? For example we have the dumb blondes,

the nerds, the stupid jocks, the snobby businessmen, the hillbillies, the stuck up rich bitches and the trailer trash.

Stereotypes exist in all races, colors, and types of people so why do we have them? What real purpose do they serve? and why are the stereotypes of minority groups seen as a worse injustice then those placed on other groups?

Anyway just a thought to ponder!