Aside from slavery, it was about whether the US would end up as a British economic colony or have its own industrial and economic basis, and the South was on the wrong side of that proposition as well.
It is worth mentioning that Robert E. Lee was morally opposed to slavery, and was originally asked by Lincoln to be the commanding General for the North.
Could you explain that, please? I have a degree in History, many advanced credits beyond that, and in general am somewhat of a history bug, and I have never before this heard that the South wanted to and fought to end up being a British economic colony.