When the war was over, both sides by and large put it behind them and went home. The sons and grandsons, and their daughters, of confederate soldiers have fought and died for this country. They did not try to destroy the United States. They simply wanted to be left alone. Right or wrong, slavery was in the Constitution. That was the way to solve the problem, given time. They were not given that time.
With our modern sensibilities, we know how wrong slavery was. Mr. Martin should focus on where it still exists. My GGF and two great uncles did not own any slaves. They fought for their state, a concept we may find hard to understand, as our loyalty is to our country.
If the jihadists would cease trying to establish a world wide Caliphate, complete with the subjigation of women, and obliteration of Israel, we would go home and leave them alone. Stan