In the case of removing civil war statues most of the ones being removed were erected long after the civil war ended, and were erected in opposition to rising pressure for civil rights for black people. See [1] and [2].

What's the case for not removing them?

[1] https://www.history.com/news/how-the-u-s-got-so-many-confede...

[2] https://www.npr.org/2017/08/20/544266880/confederate-statues...