A couple of things about that flag;
It represents only four years of events for the southern states but it dredges up four hundred years of pain and humiliation for slaves and their ancestors. Why can't you let the flag disappear, its been almost 150 years and so much has happened since and before then that warrants more of our attention. Of course you're going to say the war wasn't over slavery but states' rights, but states' rights for what...their right for slaves.
Some say its hate and not heritage, well there is such a thing as bad parts of one's heritage. The south has a rich cultural background that is ignored and overshadowed because of that flag. And as far as the patriotism of those who fly it; they claim their allegiance to the American flag and support our current US troops and are quick to accuse others of being unpatriotic, well guess what the CSA was nothing but a bunch of traders. They shot at their own countrymen, their own flag, their own government. That flag brings shame and humiliation to the south and the condemnation from the north that we are backwards and unsophisticated. Its an image we need to let go and then maybe we can finally bring in some commerce and money to the region. As you can tell I am indeed southern myself so this is not an outsider talking about something he doesn't understand.