So this guy's book is about how one or two statues or pictures of Confederate blacks were slaves, and that disproves any black soldiers?
Does this guy know that there were black freedman in the south? Much like Romans, Southerners were known to free slaves who had served them well, or as part of their will. Freed blacks lived and worked in the south, and some enlisted. End of story. It is true that there were black Confederates.
Lets look at this guy's level of scholarship:
"After war broke out in 1861, thousands of enslaved men were forced to accompany their masters into the army as body servants or camp slaves.... "It’s absolutely important to think of these enslaved men as the cornerstone or foundation of any Confederate army"
Dude - Do you know what a batman is? A serving soldier who's job it is to "go out to bat" for an officer - To fetch his meals, to launder his clothes, find him a nice billet and to toss out his whores once he's done with them. He's a solider, subject to military discipline, including flogging or execution if he is lax in his duties or deserts. He cannot leave the army. He cannot abandon his officer. He's not a slave, but he is a servant. And the officer can't deal without one. Some officers had literal servants.
Equally - Every army of this era (and maybe after) used impressed labour, including prisoners and forced locals. It was a lot of work moving an army around, and so they forced people to do the work. Sometimes with bribery, but sometimes the just said "dig the fucking hole" and pointed guns.
The myth here is that the North farted rainbows and would never do wrong by the black man. The North was a pack of tossers who couldn't agree the brewery to organise a piss up in. It took for fucking ever to defeat the south, when it should have taken about 6 minutes. A lot of black people suffered horribly from the war happening, and particularly because the North was so shit at it. Also reconstruction was shit-awful.
I'm just saying... Think more.