I don't think this is accurate. There are, or perhaps until recently were, a large number of people in the South who flew that flag out of a sense of regional pride and cohesion, and who had absolutely no problem with black people. Of course, that's not enough to forgive flying it - as a Jew I wouldn't be happy about a German person flying a Swastika, even if the only meaning it had for them was a benign pride in German accomplishments.
Still, though, it's important to recognize the wholesome impulse to celebrate the South, as it is a distinct region with its own valuable culture. A few years back there was an attempt to replace the Stars and Bars with a new "Southern Pride" flag [1]. Predictably, it's bland garbage.