I never followed that part of American history much. I learned about the Civil War in school but I didn’t find it interesting. Some people find it VERY interesting though. Some people do mock battles, reliving battles that happened in their hometowns and things.
For a lot of people, he represents “What could have been”. The South has a different character than the North and for many in the South, they feel they should have been separate and had their own nation, independent of the North.
Or they could have won and moved the capital of the country to the South and ran things in the way they thought was best.
I don’t really know for sure. I vaguely remember that of the two Generals, Robert E Lee from the South and General Grant in the North, I *think” General Lee had a more solid character perhaps. But I never found this aspect of US history interesting so I never studied it deeply enough to know for sure.