Having read the essay, my main questions would be:
1.) Given that this essay is (according too its on introduction) an uncredited student essay from Cal Poly, have all of the research citations been independently confirmed and verified? (In a newspaper article, this essay would be quoted as "according to anonymous sources ...)
2a.) Where are primary citations from the counterbalancing Union reports according to the OR?
2b.) What efforts have been made to compare the contentions of this article with said Union reports?
3.) Carl Sandburgh was not at Fort Pillow and was, indeed, a rabid abolitionist. He made no bones about that fact and one would assume his version of the story to be slanted. Sandburgh's report is (at best) second-hand hearsay and his objectivity suspect from the start. Thus, he does not stand as a reliable source. Rather, using Sandburgh as the primary resource for one side of the issue merely serves to further unbalance the objectivity of the essay.
4.) Are the cited primary resources a case of the Confederates claiming spoils as the victors by declaring themselves to have been the "good guys"?
Again - than you for the thoughtful nature of the post. I hope you understand that this response is intended to convey equally respectful questions that would facilitate objective discussion between gentlemen.
The truth of battle reports is usually somewhere in between the contentions of the two sides.