That is the majority opinion. There has always been a a minority who has disagreed. I could easily refute all your points but I'll go with the two impacting the Northern Home front most.
An abolitionist speaks up. Someone yells back "My brother/husband/son/father is dead because of dumb self rightous------- like you." Abolitionist has rotten food or bricks thrown at them. There is just as large a crowd in the North who wish not to repeat the "foolishness" of the States War.
Irish man see the blacks competing for the low rung jobs. Irish man burns down the black man's home while their cousin on the police force looks the other way. Their other cousin is lace curtian Irish and is starting to rise up the social order, going to college, introducing their sister to their old money class chum. Perhaps when their hiring they'll choose their distant cousin over the black who should go back south, in their mind.
That isn't every situation and every interaction but situations like this are likely more common than screams for revenge and class solidarity, at least in tls where tensions between the USA/CSA aren't stoked.
The others, like the Confederacy can't settle borders or states will secede from the south are based off two premises. One is that the military and political figures of both sides, who have just seen a devastating war, want to fight round two anytime soon and won't work hard to avoid such a war. The second is that the Confederates are too stupid to realize their are more Yankees than them, that industrialization is key to survival, and that if we secede from each other we are weakening ourselves.
The Confederacy didn't hold on as long as they did by being that dumb. The racists among them didn't win the peace and reimpose segregation by being that dumb.
I think our low estimation of the chances decent USA-CSA relations comes down our dislike of the Confederacy and also all the issues that are still with us from that time. It is essentially the reversed image of rosie, earlier pieces of peace and harmony like Churchill's "If Lee had not won at Gettysburg" or Kantor's "If The South Had Won The Civil War".
It, in a word, has as much basis in reality as Lost Cause Mythology did in 1900, which is some, but not all, and creating a prism that is comforting to how we'd like to view reality rather than reality itself.
Great post. It really does seem like a lot of the modern discussion around this stuff just seems like they've taken the Lost Cause mythology and reversed it (ie, all the villains become heros and all the heros become villains, but the narrative otherwise stays the exact same). The great point made by C. Vann Woodward...was that most of the Lost Cause mythology really was just made up, so you don't get any closer to the reality by just reversing it.
For example, the Lost Cause mythology makes Sherman into this monster who pillaged the South because he hated the South (and that's bad!). The modern mythology now talks about how he's some great hero for scouring the evil South and making them pay for slavery. In reality, Sherman wasn't even hated in the South after the Civil War. It's not like he actually tried to kill people, and he justified the scorched earth tactics by genuinely wanting the war to end faster. His personal politics were probably rather inegalitarian (sympathethic to the Southern Democrats, unsympathethic to the freedman).
Also broadly speaking, there's also this Daniel Goldhagen-style belief that every Southerner was just inherently going to be an evil white supremacist by virtue of being a white supremacist. And obviously, the South was a racist place (similar to how Weimar Germany was anti-semitic), but there are other reasons to explain Jim Crow than "this ethnic outgroup is just inherently bad." It's actually kind of an interesting comparison.
To vastly oversimplify it, Goldhagen has this theory that German culture dating back to the medieval ages was inherently eliminationist anti-semitic and that this explains the Holocaust. Broadly speaking, this is a very unpopular historical theory, especially in Israel and America, but it is more popular in Germany itself. Probably because 1) it fits into the German self-flagellation historical narrative and 2) it absolves current generations of possible anti-semitism (ie, the rationale is that if anti-semitism was an evil bad thing of the evil bad Old Germany, then New Germany has absolved itself completely). I kind of see the Reverse Lost Cause as an American version of that. It's superficially fashionable to bash old white Americans for whatever reasons, but in doing so, it also absolves the modern speaker of the same crimes (ie, by treating racism as just an inherent trait of the evil Old South, the New America can be totally absolved, instead of applying the lessons of the past to today).
It's not like "military occupation ended in 1876 and the South was immediately taken over by evil KKK Nazis." Terrorism asides, biracial political coalitions actually remained common in the South from 1876-1890. The one-party Jim Crow regimes only popped up after the upper-classes in the South, instilled with scientific racism (prevalent among the upper classes of both the South & North and really almost entire industrialized world), were terrified at biracial populist political alliances between blacks and poorer whites - and they responded by lining up behind the most racist people they could find to disenfranchise all the blacks (and many of the poor whites). Obviously, not to violate the current politics rules, but that historical takeaway should provide a more politically troubling and relevant political lesson to almost everyone today than "Jim Crow happened because Southerners are just an inherently evil and racist people."