I would argue that racists wouldn't vote for a person of color. Unless if you go by the 2020 definition of racist, which is basically a buzz word used by angry leftists and Twitter activists who can't think of any legitimate criticism for their political opponents.
If you go by the swing map, this really reinforces my idea. What I would argue is the most racist state of the union, Arkansas, swung hardest against Obama. White voters in West Virginia, Alabama, Tennessee, Kentucky, Mississippi, and Louisiana also swung hard R. These Deep South and Appalachian states have a pretty long history with racism against African Americans.
I would say this is mostly accurate, but you are ignoring the white racists who support Obama because it be some kind of "wake call as to why integration was bad".