The word appears 30 times.
The character of Eugene Gant is generally believed to be a depiction of Wolfe himself. The novel covers the span of time from Eugene's birth to the age of 19. The setting is the fictional town and state of Altamont, Catawba, a fictionalization of his home town, Asheville, North Carolina.
Given that the time period starts in 1910 or so, and is in North Carolina (where I have personal knowledge of the racist attitudes of the time) it is not surprising that the word is used.
I personally recall people in Spruce Pine, NC being proud of the fact that, at one point in time, they rounded up all the black folk in the town and sent them away on the railroad. This was 30+ years ago, but I wonder if the people of that town are still proud of that fact.
Not yet documented