Considering how long all parts of the country romanticized the confederacy that mentality is going to take some time to correct.
Recognizing and honoring guys like Lee was a way of expediating the process of bringing the south back into the union. Imean all the way up until, I dunno, the 80s glorifying the confederacy and the "rebels" went relatively unchallenged in the mainstream media. The Dukes of Hazard I think is a good example of how "fair game" southern confederacy references were until recently. A show like that would never fly today, which is good.
We've basically got like 120+ years of damage control that was written in favor of the south to unwrite.
It's similar to the Redskins name. It's something we've been doing wrong forever, but just the fact that the mistake has been repeated for so long makes some people view it as evidence of being "okay" as they remember times when there was little push against it.