Predictably, those defending the continued use of a symbol representing people who staged a violent, treasonous uprising to defend their ability to own human beings try to downplay that part of it all, instead focusing on how it's just a symbol of Southern heritage (while of course, leaving out exactly what that heritage entails). So much like the leaders of the confederacy would have been surprised to learn their treason was not about slavery or racism, given how often they spoke about defending slavery and upholding the racist social order, it would probably surprise the folks who came up with the confederate flag to learn that it's apparently not about slavery or racism, either.
But how can we know what those folks were thinking? If only there were some sort of written record of their ideas. Oh, it turns out there is. Here's William Tappan Thompson, the designer of the confederate flag, on why he designed it:
As a people we are fighting to maintain the Heaven-ordained supremacy of the white man over the inferior or colored race; a white flag would thus be emblematical of our cause. ... As a national emblem, it is significant of our higher cause, the cause of a superior race, and a higher civilization contending against ignorance, infidelity, and barbarism.It's funny; I've read that quote several times and don't see anything about Southern heritage. I do see a whole bunch of stuff about racism, though. But I thought that flag wasn't about racism! Someone should really inform the guy who designed it.
—William T. Thompson (1863), Daily Morning News (Savannah, Georgia)
Of course, it's very important to remember that flag is just one small token of our nation's horrible history of racism and that removing it is, at best, a symbolic gesture. And furthermore that taking it down simply for pr reasons is missing the entire point. That being said, let's please have a national conversation about race and try to begin to heal the wounds and make reparations. But let's do that without the shadow of a confederate flag flying over us.