Though technically possible, the acceptance of that explanation without any substantiation violates Ockham's razor (i.e. it is unnecessarily complex to conclude, based on the existing evidence, that they would have engaged in a practice outside of the ordinary and expected use of firearms in a wartime military presentation). Further, even if one were to accept that assumption about the display, they were reported to have gone to the lines during a raid a few days earlier (which would have served no purpose had they not been armed, not to mention the Richmond brigade's known combat before Sailor's Creek.
The newspapers you cite, in the CSA capital a couple of weeks before the fall of the city, were doubtless propaganda outlets for a desparate rebel government and cannot be relied upon as confirmation of anything.
Nonsense. Dismissing them on your own arbitrary assumption that they all just must have been propaganda outlets is not a valid logical exercise. As it stands, those newspaper reports are the only eyewitness accounts entered into the material of this discussion to date. All of them say that the reception was favorable and, barring any account that you have to offer suggesting anything otherwise, they are the only primary material we have to go by.
In other words, if your claim is true you need to support it with some evidence that counters my evidence that it is not true. Quod gratis asseritur, gratis negatur.
Much more indicative of the attitude of blacks in Richmond was their reception to President Lincoln a few days later, yelling "Glory to God", calling him "Father Abraham", and falling to their knees to thank him.
You are confusing the subject by altering it from Richmond's reception of the black troops to the reception of Lincoln given by non-soldier blacks in Richmond. That is a different subject entirely and bears little relevance upon the former issue.
If there really were units of black rebels fighting the Union forces at the end of the war, where are the accounts from astonished Union troops?
Considering that the yankees had reported encountering black confederates dating all the way back to Manassas, no reason exists for them to have been astonished. As for the accounts, like I previously noted, one is quoted on the historical marker at the battle site. They are almost certainly others somewhere in either the official records (which represent about 10% of the government documents) or in the union provost marshall records (where most of the other 90% are). The problem is finding it. With time, I will try to find something in the official records if I can but there are about 100 lightly indexed volumes of them to go through. If they aren't there and are instead in the provost marshall records, that task will be significantly harder without a specific call number because the provost marshall records are on almost entirely unindexed microfilm that probably exceeds a thousand rolls.
Surely, such raw recruits would have been smashed immediately by the battle-hardened Union forces.
The markers on site say that they held off the first cavalry assault but fell to the second one. Would a more experienced group have lasted longer? Who knows. But then again, this is also the civil war where 40 confederate dockworkers once held off a battle-hardened northern navy flotilla of over 20 ships and several thousand men. So experience as a speculative device isn't indicative of much of anything.
Why are there no accounts of Union forces taking black rebel prisoners?
If I recall correctly, there actually were. But again, it's a matter of finding them in the records and i'll happily keep an eye out. There is at least one I can verify without having to search. The CSS Shenandoah surrendered in november 1865 after several months at sea and among them was Edward Weeks, a black confederate sailor.
As for the white commanders of the black rebel regiments (you were talking about there being many, remember?), seemingly every former rebel and his brother wrote about their Civil War experiences. Why did no one write the sure-fire bestseller "I Commanded a Regiment of Black Rebel Troops"? Etc.
What on earth are you talking about, Partisan? Several accounts saying exactly that existed. Robert Waitt, a commander in the Winder-Jackson battallion, documented it as follows: "I had the pleasure in turning over to Dr. Major Chambliss a portion of my Negro companty to be attached to his command. Allow me to state, Sir, that they behaved in an extraordinary suitable manner." Turner wrote of the blacks in his brigade that "The knowledge of the military art they already exhibit was something remarkable. They move with evident pride and satisfaction to themselves." Captain J.B. Briggs also wrote of the Chickamauga incident I mentioned earlier (he was the officer who took them to the line).