And that is a big part of the problem and contributes to the lingering feelings in the south.
Once it became clear that the war was effectively won by the north there was no need for the Union army to march through the south destroying everything they could and laying waste to half of the nation.
That was done out of petty bitterness and a an impulse to get even or get some payback.
Imagine if after the end of WWII hostilities the US had spent a year or so sending armies through Germany, Japan and Italy, raping plundering, destroying or stealing everything that was left. Burning the homes and possessions of civilians, turning them out into the streets with nothing more than the clothes on their backs, taking away what little they had left - their homes, lands and livelihoods.
Relations between the US and those countries might still be strained, to say the least.
Germany WAS leveled. Japan was ruined.
The south should have surrendered.
Also, unlike what we did in WWII, once we devastated the south we did nothing to build it up. It fell into bitterness and poverty like nothing the country had suffered up until then. Just read the short stories of Thomas Wolfe where he recounts his family’s suffering during Reconstruction! Shocking, to say the least. It’s akin to what the allies did after WWI - doing nothing to alleviate the poverty of Germany and laying the foundation for WWII.