The diary entry is from July 17, 1864. Kentucky had largely avoided African American recruitment until the spring of 1864, but when it started, it was full force. By the end of the war only Louisiana had sent more black soldiers into Union service than Kentucky. It wasn't unusual to find opposition to black soldiers in the Union army in 1863 and 1864, racism was prevalent across the North as well as the South, but Kentucky's opposition was particularly vitriolic due largely to it being a state where slavery was legal and where the opportunities were few and far between for African Americans to show what they were capable of in society.
The diary entry reads, "On the 17th of July (1864) I was detailed for picket duty and saw three thousand negro soldiers on grand review, a black cloud to see. On the 18th I was relieved of duty. Here I became dissatisfied as a soldier on account of the negro, negro, negro. On the 23rd we began to get ready to leave this negro hole and on the 24th, to our great joy and gladness, we were sent into camp near Danville."
His choice of words is very interesting. Using the phrase, "black cloud" obviously connotes that he didn't see black troops as a positive for the future. His repetition, "on account of the negro, negro, negro" indicates that he emphasizing this negative point. And, labeling the camp he was in a "black hole" and leaving "to our great joy and gladness" certainly does not show any empathy or liking for his black comrades. I would love to find this diary and see if his opinion of USCT soldiers changed over the rest of his military service, or if he held to his prejudiced statements.