Most of the statues went up in the twentieth century. Specifically to intimate Civil Right proponents by not showing what we've learned from the past, but by threatening to repeat it if they continued to pursue their equal rights as US citizens.
The statues, put up by Democrats were to honor Confederate personalities. The intimidation came from the KKK, which were also Democrats. I can understand why Democrats want to remove them now. Best not to have reminders of past allegiances