Greetings Bennie:
Since I appreciate your skill at confusing an argument with facts, I've included the url below.
The Frederick Douglass Papers can be found at the Library of Congress. It includes a searchable database. Plugging in the mythical terminology of black confederates, colored, negro etc results in bupkiss, nada, zip.
Plugging in Civil War brings up Douglass' description of the confederacy as "An Oligarchy."
K Wyer Lane