>>509434652 (OP)The premise of this question is kind of misleading in that it implies that punishing the confederates more would have somehow made your average southern Joe view the confederacy less favorably. As a matter of fact there’s an argument to be made that the opposite is true, that the average southerner would be more resentful if every confederate rebel had been hung/put in prison for life after the end of the civil war, or actions had been taken solely to make life harder for southerners to punish them for the civil war. The north was looking to re-unite with the southern states after all rather than rule over them which required tensions be addressed with a level of care rather than brute force.
That being said, there are definitely areas in which the north could have done much better in post-civil war reconstruction. Many Africans who were freed found themselves without possessions after the civil war and the U.S.’s failure to provide them with means by which to properly integrate into southern society would lead to the Jim Crow era, manifesting racial tensions which continue to echo into modern politics. While American laws and views towards freedom of speech make this sort of thing more difficult to control, the north definitely could have played a stronger role in regulating the education of children post-war on the importance of the civil war and defeat of the confederacy to America, rather than allowing “lost cause” and “war of northern aggression” narratives to be circulated by more resentful southerners.
Honestly I dunno how much of a difference that would make with relation to modern politics, though. Even if post-war reconstruction had gone better you’d still inevitably have resentful, prejudiced portions of the population who would vote accordingly given how democracy needs to empower everyone to vote to work.