Well aware of that. All good information.
CSA refusal to treat recaptured slaves or black POWs in general equally was a major cause of the breakdown of prisoner exchange in the last year of the war and the resulting tragedies at Andersonville and elsewhere.
But only about 40,000 black soldiers died during the war, as opposed to well over 600,000 white soldiers. Which is what I originally said.
That relatively few black soldiers died, especially in combat, is due to early concerns that they wouldn’t be able to fight effectively, and later (often justified) concerns that they shouldn’t be exposed to the greater risk of capture or massacre on the battlefield.
Possibly the greatest opportunity of the war, the Battle of the Crater, was screwed up at least partially because the brass pulled out black regiments specially trained to spearhead the attack for fear that they would be accused of sacrificing black rather than white soldiers, replacing them with untrained and confused white regiments.
***
Battle of the Crater
"After weeks of preparation, on July 30 the Federals exploded a mine in Maj. Gen. Ambrose E. Burnside's IX Corps sector, blowing a gap in the Confederate defenses of Petersburg, Virginia. From this propitious beginning, everything deteriorated rapidly for the Union attackers. Unit after unit charged into and around the crater, where soldiers milled in confusion. Grant considered the assault "the saddest affair I have witnessed in the war." The Confederates quickly recovered and launched several counterattacks led by Brig. Gen. William Mahone. The breach was sealed off, and the Federals were repulsed with severe casualties. Brig. Gen. Edward Ferrero's division of black soldiers was badly mauled. This may have been Grant's best chance to end the Siege of Petersburg. Instead, the soldiers settled in for another eight months of trench warfare. Burnside was relieved of command for the last time for his role in the debacle, and he was never again returned to command."