But if you follow a collection of letters from the same soldier, or follow his diary, a very dramatic change happens. Men who opposed it suddenly are for it, men who had derided the idea of "nigger soldiers" suddenly begin to pay a begrudging respect for them as fighting men.
Often soldiers from the same regiment from the rural midwest would take turns writing to their hometown newspapers, when the letters were printed their whole company would read it when the newest papers came into camp, so the entire company would more or less be of the same mind about an issue, and these newspaper letters reflect their collective thoughts, even though written by one man. They were meant for public consumption. Anyone can follow those letters through the course of the war, see how tone changes dramatically sometimes with the change of events.
Those soldier letters published in rural Northern hometown newspapers were not shy about expressing complete contempt or mockery for the use of negroes and darkies or whatever derogatory term they used. These Northern soldiers were absolutely appalled by the contrabands when the faces them bu the dozens or hundreds.
But Alan, the tone changed in later letters, they not only accepted black soldiers they encouraged more of it, and they openly told the folks back home to support it.