One of my readers was kind enough to pass on the following video, which was originally used as part of a training course for National Park Service interpreters. The video includes interviews with various interpreters on the necessity and challenges associated with introducing the cause of the war on Civil War battlefields. There are a number of perspectives presented, but all convey the importance of doing so.
NPS Talks Slavery and Battlefield Interpretation
Searching for Black Confederates: The Civil War’s Most Persistent Myth
“Levin’s study is the first of its kind to blueprint and then debunk the mythology of enslaved African Americans who allegedly served voluntarily in behalf of the Confederacy.”–Journal of Southern History