>>>According to the 1860 census there were, at best, about 23,000 free black men of military age in the entire south. Did each of them enlist 4 times?<<<
They were enlisted near the end of the war, several years after the 1860 census. The were promised freedom if they would join the CSA.
I suppose you have some evidence to back this up? I'm curious to see it and I wonder how they could accomplish it, especially since the confederate constitution and every state constitution in place in the confederacy at the time all had clauses specifically stating that neither congress nor the legislatures could not pass laws manumitting slaves. Legally what you claim is impossible.