Maybe thirty years ago it wasn't unusual for Southern high-school marching bands to carry the Confederate flag along with the U.S. flag and their state flag. Sometimes they would play "Dixie" as one of their brass band favorites.   

I don't know just when the practice became common or what the ultimate "message" behind it was supposed to be. It made Yankees like me, who'd seen the flag in modern times mainly in pix of KKK rallies, kind of uncomfortable. It must have made African Americans even more uncomfortable, no matter how it may have been rationalized.

When I mentioned the likely offensiveness of the flag to a couple of intelligent, liberal (white) friends, they were surprised nad said, "It's just the flag of the South." They'd grown up seeing it and it never registered beyond that. They understood my point but thought it was exaggerated. They were not racists and the flag didn't "stand for" racism to them.

On the other hand, they weren't flying one themselves. And it was a long, long time ago.