This article only talks about slaves that we can assume were forced to fight for the Confederacy. What is even less well known is that there were free blacks that fought for the CSA. In New Orleans during the Civil War there were quite a few black free tradesmen. When Union General Butler attacked New Orleans, residents defended the city composed of both white and black CSA soldiers. They were defending their city from attack. Butler occupied the city and imposed martial law, with its attendant rapes and pillaging of the fair city of New Orleans. He it was who said that any woman you see can be assumed to be a 'lady of the evening' and you could have your way with her. The false impression that New Orleans girls are tramps lingers to this day.
The reason Butler issued the order was the "ladies" weren't acting like ladies. They were yelling insults and verbal abuse at any Union soldier. Butler issued the order to the effect any woman not acting like a lady wouldn't be treated as one.