Just imagined it or don't understand it. There's zero incest in the show, and zero hate crimes. Other than the flag and name of the car, there's nothing racist about it at all, and that flag wasn't perceived as a racist symbol back then, as illogical as that may seem. When black people do appear in the show, which admittedly is rare, they're always equals to the Duke boys. The show is just good fun. If there's any theme to it at all, it's that it's cool to make money with moonshine, and flaunt the law, while making fools of law enforcement.