I spent a lot of time in Alabama, and my roots, on both sides, were Southern way back until they cross the pond to N. Europe, yet I am a Liberal in the classical sense so I belive I have a unique perspective on this.
There are MANY reasons Southerners become enamored with the Confederate flag. For many it is a symbol of being an underdog, an opressed majority so to speak. While middle class whites are the huge majority in the South, they often are dissatisfied with their position in the world, and pretending to be an oppressed minority helps to remove the responsability from himself to something beyond his controll, making it easier to accept.
Others honestly conisder it a symbol of their heratage and history, they rsaw it in their grandparents homes and their parents homes and it is a symbol of a culture they belong to.
Others use it as a symbol of hate and try to antagonise people they dont like.
And others use it as a form of rebellion and counterculture to prove to themselves they are different or better.