The thing white people fear most is being shunned by other white people. I believe (naively, perhaps) that there are whites who genuinely would like not to display racism, but the thought of being dropped by friends and family and being treated as a "traitor" to their tribe keeps them in line. Successful, rigid societies know how to ostracize their non-conformists into behaving "properly."

That's one of the reasons why most Democratic contenders for higher office have to have their "moment of proving that they're not TOO friendly to black people" so as not to lose white support entirely. It's why Democrats are afraid to say that their "rural problem" is not one of economics, but one of culture and racism. There's still a "them" and an "us," and until people lose their fear of crossing that divide, they'll never realize that everyone can, in fact, "win." There is a real opportunity cost for racism, and not enough people appreciate that it's their loss too.