I once heard a talk about the desegregation of the Army during the Korean War. It seems the Army believed that Southerners were better suited as officers for black units (when the officers were white and the enlisted men were black) because they "understood" black people better than Northern whites.
Johnson's comments about MacArthur are interesting. I know a survivor of the Bataan Death March who was not a fan of MacArthur (he is still alive but apparently has dementia--haven't seen him in years).
I thought Truman desegregated the military
My family, too, knew someone who survived the Bataan march.
The man was highly critical of MacArthur, saying the General evacuated his furniture rather than Army nurses, leaving them to the Japanese.