Battle of Olustee

This February 20th was the 150th anniversary of the Battle of Olustee.
It was a major battle in Florida, during the Civil War.
Why is there currently so much controversy over building a memorial to the Union soldiers who died there?
150 years later, are Northern and Southern states divided?
If so, over what?
Slavery is abolished.
Is the recent controversy just a fight over commemoration, or is it something else?