When you claim “black soldiers fought in the Confederacy” it depends on what you mean by “black,” “soldiers,” and “fought.” Charles, I substantively agree, but here’s how you bend the logic all the way round.
“Black” in one case to my knowledge (but can’t find a link now) refers to a 1/8 black naval officer whose family owned a plantation with slaves. He was white for all intents and purposes.
Many wealthy Southerners had servants in camp cook, clean, etc. They were black, and they were there, but “fought” or “soldiers” is a stretch indeed.

If you leave out all the nitpickey details, you could “interpret” those cases until “black” “soldiers” “fought” in the Confederacy.