“The modern justification for all of the bad things that were done in the Civil War is slavery”
This view of the Civil Was is just as incomplete/incorrect as the “lost cause” tenet that slavery had absolutely nothing to do with secession or the coming of war.
Because slavery in the South would have absolutely disappeared in the subsequent five years if the South had remained in the Union.
Yes, it was all about that thing that wouldn't have changed at all.