What is the essence of chapter 28, "We Are All Americans," in Battle Cry of Freedom?

The essence of chapter 28, "We Are All Americans," is the end of the Civil War and how the passage of the Thirteenth Amendment affected the government, the slaves, and the South. The chapter also discusses the Confederacy's movement toward arming slaves and having them fight on the battlefields.
The people in favor of arming slaves began to take precedence. One important person who supported it was Robert E. Lee. He also believed that the ones who served should be freed. However, many Southerners believed it would upset the social structure of the South. The chapter uses its first section to discuss the topic and says that ultimately the black men who were made to serve never saw battle and were not freed by the South.
The second section discusses the Thirteenth Amendment and how Lincoln saw his reelection as a "mandate" for its passage. He wanted both Democrats and Republicans to vote for it even though Republicans would have control of the legislature in the next Congress. The vote passed 119 to 56. The author notes that black people were there in the congressional galleries to hear about the passage of the amendment, which was important because they were barred from it until 1864. It also discusses the Freedman's Bureau and Lincoln's movement toward the left on the political spectrum.
The third and final section talks about how Ulysses S. Grant and the Northern Army took Richmond back. According to the author, President Lincoln visited and was celebrated by the now-freed slaves there; some of them even touched him to be positive he was real. He told one man not to kneel to him, because he was free and should only kneel before God. General Lee surrendered at Appomattox Courthouse. The chapter discusses the reaction of the country to the end of the war and ends with a threat against President Lincoln by John Wilkes Booth.