Perhaps in your citation lies the key to the truth of Fort Pillow:
"What happened under the bluffs was described by Lieutenant Learning as a "horrid work of butchery," which continued from the fall of the fort "until dark and at intervals throughout the night. Others who testified, including both those who were there and those who were not, were more profuse and harrowing in their detailed accounts of rebel savagery in the 128 pages of the report of the Congressional committee. And there can be no doubt, nor has it ever been denied, that some men -perhaps a considerable number-were shot after they, as individuals, were seeking to surrender."
One side's "massacre" was another side's "hard-fought victory." The politicos on both sides would then advocate their positions in the press on both sides. And both sides would lose track of the fact that valiant men on both sides would not return home.
If the scholars would ring in -- on this thread or another -- would be a fine thing. If not, c'est la vie. My point remains that war (at best) is barely restrained chaos. At worst it is propaganda writ with the blood of valiant men of both sides who are unaware that they are only "ink".
FWIW- I have recently been researching and mapping the Union and Confederate transit routes from the Battle of Prairie Grove to the Battle of Van Buren and have started on the movement routes from the area of Ozark (AR) to the Battle of Prairie Grove. My focus is not "who were the good guys" -- it is how did the war flow and how would I follow it in my car in 2009. If I would honor the valiant men as they struggled their way from battle to battle, where would I go to do so.
Follow the flow of the war along the arteries of the nation and you get a clear picture and you get a very clear picture of the overall affliction.