My take on it is that Forrest makes a useful scapegoat for a despicable institution doomed to failure. If an Ironman didn't take control of the Confederacy and amend its constitution to strengthen its executive, how would the rest of the state hope to remain intact?
Yes, the CSA was near bankrupt for most of its existence, oppressed its slaves and lower class whites to favor its planter elite, and had an inflation rate of 400% a year, but it probably either that or simply collapse.
The sordid events of the 1890s are the price a nation pays for abusing 80~90% of its people; if anything the Union should have tried to intervene earlier--but if those events of the 1890s hadn't occured, we'd probably have an intergenerational problem of Southrons constantly seceding over every stupid thing they didn't like. A dystopian outcome where 1/3rd of the population died of starvation, reprisials for slavery, or diseases caused from broken agriculture killed the idea of an independent south DEAD.
The CSA was the worst thing the South ever did. Before 1860, the South could rightly claim to have been a major influence on the United States as a whole. By the time the former CSA was readmitted as three states to the USA, they'd moved to dead last in wealth, influence and culture. How much of that was due to things like putting New Orleans to the torch and how much was due to decades of oppressive rule is hard to determine, but either way, the South held and holds today remarkably little power.
What if, instead of there being 3 Southern states (plus Tennessee and *Virginia*) there were 11 in congress? With free blacks added into the mix, the former CSA would have had a larger representation in the House than it did pre-secession as well. If the CSA had been quickly defeated, they'd still have at least some power nationally again. As things stand now, they're still an underdeveloped backwater known for electing Black Socialists as governors.
At least guys like Martin L. King and John Lewis have done great good for their people, but they've had a long road to run.