You have no idea what I think about capital punishment. You are welcome to your opinion but it seems to me more likely that the confederates decided to kill a few to make up for their embarassment at having been caught with their pants down.
I did not presume to devine your opinion of capital punishment. I only commented on the (ill)logic of your stated position as it related to the execution of these prisoners.
You may be right that these men were executed only out of embarassment and that would be a war crime in my book. But we do not know that that was the case. We do know, evidently, that they were commiting sabotage behind enemy lines out of uniform.
Do we know that Forrest's men, for example, were captured raiding behind lines, out of uniform, i.e. with no indicia at all?