With the popularity of “The Birth Of A Nation”, rising KKK membership, and deteriorating race relations, the Lost Cause became a bigger part of American culture. KKK membership rose all around America, not just in southern states.
The historians had gotten what they wanted, there was a general consensus of what the American character was, and it was based on the frontier, not on slavery. This is why Western movies were so popular, because they were built in part on the denial of the role of slavery in American history.
In the early 1900s, movies would portray confederate heros as morally equivalent to the union. The movie “Gone With The Wind” portrayed reconstruction as raveging the south, and destroying their way of life.
Eventually the Lost Cause made its way into history textbooks, with the sponsorship of the United Daughters of the Confederacy. Only recently have southern textbooks started to get rid of Lost Cause ideology.
As the Lost Cause got more immersed in American culture, the ideology was watered down. Eventually people started to see Confederate symbols as “heritage not hate”. The Confederate flag gave southern people a sense of identity.
Things started to change with the civil rights movement in the 1960s. People remembered the Confederate flags being used to support Jim Crow, so they wanted to get rid of them. As more left leaning people became historians, they revised history, and revealed the link between the myth of the Lost Cause and racism.
There was conservative backlash as the people saw the Lost Cause myth challenged. Lost Causers preferred to dilute the truth for the sake of preserving their identity, but eventually the new left won out, and a more accurate version of history is usually taught in school.
What all of this means is that people aren’t necessarily aware of the darker connotations when waving Confederate flags. They may genuinely believe it represents heritage and their southern identity, not hate.
But more recently with things like the Charleston church shooting, the Confederate flag has become more associated with being a hate symbol, leading South Carolina to finally take it down.
After George Floyd’s death in 2020, there was once again a great push to get rid of Confederate memorials and symbols, and Mississippi voted to redesign their state flag to stop including a Confederate flag symbol.
The arguments and debates continue, but the Lost Cause remains a pseudo-historical myth, mostly used to promote and support an insane amount of racism throughout history.