I understand that. What you are saying is true, lIke it or not. But what if it was not?
How is this supposed to work? What might Southerners that have largely conservative beliefs but might not be racist do? And it's not like Democrats are competing for the Southern white racist demographic in the first place.
As you might see, the map has Democrats in the 30-50% range. This leaves 30%-40% for the GOP and the remainder to a New Dixiecrat party. Democrats need only a few more whites to win most of those states if the white vote is split.