An excellent example. By reframing the Civil War as a "war of northen aggression" having nothing to do with slavery, whites in the south could avoid any residual feelings of shame associated with the position they took on slavery. They could instead take pride in their ancestors who stood up to an evil north, rather than trying to reconcile their heritage of slavery with a more modern view of civil rights.
We are seeing the same thing happen today with the attempted cancellation of both CRT and the 1619 project. These studies of history make many white people feel bad, because it reminds them that a significant part of this country came from the labor of slaves. This make them feel - not bad, exactly, but like they cannot be as proud of their history as they otherwise could be. "Make America Great Again" doesn't work if those halcyon days included slavery (or enforced segregation, or redlining, or any of the other structural racisms that the early and mid US incorporated.)
So they try to ban it. They realize that banning history is something of a bad look, so they dress up the ban in flowery language and mix in a few "won't someone please think of the children" memes. We've seen these a lot lately - "why are teachers teaching our children to hate themselves?" CRT teaches kids "to be ashamed that they are white." One theoretically real child tearfully asked her far-right mother "Why am I hated so much?" - and then supposedly needed therapy to overcome all the damage that CRT did. (How fortunate that that child did it just in time for Marsha Blackburn's political campaign.)
Others spend thousands of words trying to define CRT to mean something other than CRT. It's an "unremitting attack on Western institutions." It teaches that "America is systemically racist and must be dismantled." It was created by Karl Marx to destroy democracy. It is a "monstrous evil" that gives black people "the whip handle" over white people. (That last was from Pat Robertson; what a fascinating metaphor to use when one is advocating ignoring what slavery did to the country.)
Underlying all this blather is a simple belief common amongst the right - that education can and should be curtailed because it makes some people feel uncomfortable or threatened. We have seen several examples right here on this forum.
George Orwell once said that "he who controls the past controls the future." Conservatives are trying to take control of the past and alter it to something that works better for them. The question is - will we let them?