Why did some people in the south refer to the civil war as a rich man's war and a poor man's fight

People in the South referred to the civil war as a rich man's war and a poor man's fight because people in the North had much more money (rich men)and were more advanced technologically speaking, while in the South the economy was still based on agriculture and slavery, making everyone much more poor (poor man). Hope this helped, have a great day :)