Uh, usually they fly them to piss off northerners, or to identify themselves as proud southerners.
No it isn’t just a reminder of the Union defeating the confederates. Why do most civil war re-enactments happen in the south and not the north? It is history, remembering history, and pride in coming from some where. It has nothing to do with slavery, or racism, as most northerners like to brand it.
Why do we have WWII memorials? Is racism against Japanese ok? Don’t you think it offends all Japanese having a statue of the Marines Raising Flag on Iwa Jima? Don’t you feel shamed of the racism that statue implies? Especially after the 2 atomic bombs being dropped? Or do you look at is as a piece of history and a tribute to those who fought, died, and should be remembered?