Dr. Orwin's position falls apart when, as the previous comments allude to, you look at when most of the monuments went up.  A graph of their construction over time shows two big spikes that correspond directly to the instigation of Jim Crow laws and the civil rights movements in the sixties and shows clearly what their true purpose has been.  As such they are indefensible in spite of the whitewashing of them by the right and apologists like Dr. Orwin.