In Chapter 9 of Howard Zinn's a People's History of the United States what is his opinion of the Civil War?

America’s Civil War, the central event in the country’s history, is dismissed by Zinn as nearly another ruse by the elites for profit. He says Lincoln only used the issue of slavery for his own personal game. Zinn claims that Lincoln failed to ban slavery in Washington DC, this is wrong. Congress banned slavery there in 1862. (Washington D.C. is not a state but a territory run by Congress) (2)