There's a reason the Civil War is also called "The war of Northern aggression"
They could not do without our resources.
Lincoln did a lot of un-American things.
The irony is he in no way wanted to destroy the southern economy; the whole point of the war was to tax it to finance the subsidies and corporate welfare that would entirely benefit the northern states. If he had lived, he most likely would have been impeached by his own 'supporters'; they impeached Andrew Johnson precisely because he intended to follow Lincoln's plans for post-war legislation.