If a feature at a National Park is more than 50 years old, then it is considered historic and protected. It would be greatly against Park regulations to remove those statues as they are now part of the Park landscape.
As an example, historians these days pretty much agree that the famous Bloody Pond at the Shiloh National Military Park did not exist as the time of battle. However, it has been a fixture on the Park’s land for many years, and it therefore cannot go away.
“If a feature at a National Park is more than 50 years old, then it is considered historic and protected.”
Not true at Cape Lookout National Seashore. They’re letting some structures over 50 years rot where they stand.