Why is junior so cynical about white teachers?

Coming from the reservation, Junior already has preconceptions about white teachers. He thinks they will treat him as lesser than white students because he is Indian. Junior has been taught that whites oppress Indians and white teachers are not any different.

The question was about chapter 4 . Thank you so much for helping but this is not the answer i need. Once again iam asking, Why is Junior so cynical about white teachers?