The Civil War, like so much of history, is in every era recast as a morality tale, and the people recasting it identify with the heroes and then brand the hated outgroup-du-jour as the villain. Yes, the South seceded due to slavery. It was a MAJOR motivating factor. The central one, in fact. But the North didn't go to war to defend slavery. They went to war to preserve geopolitical unity on this side of the Atlantic, and to defend business interests. They flat out said as much, with much flowery language. And when they did free the slaves, Lincoln mulled restricting their voting rights before being assassinated, and then a huge portion of the newly freed slaves died. Up to one in four. The government certainly had the resources to save them, they just didn't see it as expeditious to expend the political capital necessary to do so. The civil war was ugly. The lead up was ugly, and the aftermath was ugly. And neither side cared about black people in the abstract. There were no heroes, it was a senseless and disgusting slaughter born of an unresolved contradiction which has poisoned this country since its inception.