I never made the distinction between slaves or free blacks. I simply stated accurately that blacks fought for the Confederate cause.
Black Southerners fought alongside white, Hispanic, Indian, Jewish and thousands of foreign-born Southerners. They fought as documented by Union sources:
Frederick Douglass, Douglass' Monthly, IV [Sept. 1861,] pp 516 - "there are at the present moment many colored men in the Confederate Army - as real soldiers, having muskets on their shoulders, and bullets in their pockets, ready to shoot down loyal troops, and do all that soldiers may do to destroy the Federal government...There were such soldiers at Manassas and they are probably there still."
"Negroes in the Confederate Army," Journal of Negro History, Charles Wesle, Vol. 4, #3, [1919,] 244-245 - "Seventy free blacks enlisted in the Confederate Army in Lynchburg, Virginia. Sixteen companies of free men of color marched through Augusta, Georgia on their way to fight in Virginia." "The part of Adams' Brigade that the 42nd Indiana was facing were the 'Louisiana Tigers.' This name was given to Colonel Gibson's 13th Louisiana Infantry, which included five companies of 'Avegno Zouaves' who still were wearing their once dashing traditional blue jackets, red caps and red baggy trousers. These five Zouaves companies were made up of Irish, Dutch, Negroes, Spaniards, Mexicans, and Italians."
Noe, Kenneth W., Perryville: This Grand Havoc of Battle. The University of Kentucky Press, Lexington, KY, 2001. [page 270] From James G. Bates' letter to his father reprinted in the 1 May 1863 "Winchester [Indiana] Journal" [the 13th IVI ["Hoosier Regiment"] was involved in operations around the Suffolk, Virginia area in April-May 1863 ] - "I can assure you [Father,] of a certainty, that the rebels have negro soldiers in their army. One of their best sharp shooters, and the boldest of them all here is a negro. He dug himself a rifle pit last night [16 April 1863] just across the river and has been annoying our pickets opposite him very much to-day. You can see him plain enough with the naked eye, occasionally, to make sure that he is a "wooly-head," and with a spy-glass there is no mistaking him."
The 85th Indiana Volunteer Infantry reported to the Indianapolis Daily Evening Gazette that on 5 March 1863: "During the fight the [artillery] battery in charge of the 85th Indiana [Volunteer Infantry] was attacked by [*in italics*] two rebel negro regiments. [*end italics*]." After the action at Missionary Ridge, Commissary Sergeant William F. Ruby forwarded a casualty list written in camp at Ringgold, Georgia about 29 November 1863, to William S. Lingle for publication. Ruby's letter was partially reprinted in the Lafayette Daily Courier for 8 December 1863: "Ruby says among the rebel dead on the [Missionary] Ridge he saw a number of negroes in the Confederate uniform." Federal Official Records, Series I, Vol XVI Part I, pg. 805: "There were also quite a number of negroes attached to the Texas and Georgia troops, who were armed and equipped, and took part in the several engagements with my forces during the day."
Federal Official Records Series 1, Volume 15, Part 1, Pages 137-138: "Pickets were thrown out that night, and Captain Hennessy, Company E, of the Ninth Connecticut, having been sent out with his company, captured a colored rebel scout, well mounted, who had been sent out to watch our movements."
Federal Official Records, Series I, Vol. XLIX, Part II, pg. 253 - April 6, 1865: "The rebels [Forrest] are recruiting negro troops at Enterprise, Miss., and the negroes are all enrolled in the State."
Federal Official Records, Series I, Vol. XIV, pg. 24, second paragraph - "It is also difficult to state the force of the enemy, but it could not have been less than from 600 to 800. There were six companies of mounted riflemen, besides infantry, among which were a considerable number of colored men." - referring to Confederate forces opposing him at Pocotaligo, SC., Colonel B. C. Christ, 50th Pennsylvania Volunteer Infantry, official report of May 30, 1862 "Sargt said war is close to being over. saw several negros fighting for those rebels."
From the diary of James Miles, 185th N.Y.V.I., entry dated January 8, 1865 Black Southerners also demonstrated loyalties based not on ownership, subservience or fear. The Confederate Burial Mound for Camp Morton, Indiana, at Indianapolis, Indiana, has bronze tablets which list the nearly 1200 Confederates who died at that camp. Among those names are 26 Black Southerners, seven Hispanic Southerners and six Indiaan Southerners. At a time when those Black Southerners could have walked into the Camp Commander's office, taken a short oath and signed their name to walk out the gates free men obliged to no one they chose instead to stay even unto death. Your understanding of that choice is likely nonexistent.