Great question. It's not an easy straight forward answer, but rather a combination of things. Those that fly that fly see it as a symbol of independence and "don't tell me what to do" attitude. There's some racial issues of course. There's poverty in rural areas that gets mixed in - the idea that "I'm better than someone else even though my life circumstances are crappy." There's also the ignorance of history and educational levels. Mix all that in with the sense of identity into this mix and some kind of rose colored nostalgia for an imagined past. It still boggles my mind seeing a Confederate flag in the north.