I'm not sure academics redefined it so much as the colloquial usage changed. "Racist" was originally used as an alternative form of "racialist," without a negat

I'm not sure academics redefined it so much as the colloquial usage changed. "Racist" was originally used as an alternative form of "racialist," without a negative connotation, to describe people who believed in the superiority of a particular race. These people were white (supremacist) Americans. Academics still use the word in a similar way. Not my field (and please correct me if I'm wrong), but I believe there are other terms like "racial discrimination" that didn't come from white supremacist thought, and that can be used in academia to describe mistreatment of white people on the basis of their skin.