There's a pretty big difference in the institutionalization of racism between the two states. At this very moment there are statues of Confederate soldiers on the grounds of government institutions. If you're black and you have to go to trial in Bryant County, you have to walk past a 12-foot-tall statue of "our gallant Confederate soldiers". That's state-sponsored terrorism against black Americans.
By the way, Oklahoma was not even a belligerent in the American Civil War, because it did not exist until 1907. All of its institutional racism was simply imported.
Should we skip California because Native Americans were killed in the 1880s?