The original question had to be edited. I think that the effect of Jesse being the main focus of the narrative helps to illuminate how racism is a disease that impacts both White society and people of color. Jesse is shown to be an extremely disturbing construct of racism. Racism is shown to be something that impacts White people in an intensely brutal manner. The fact that Jesse can only get an erection through thinking of violence, lynchings, power, and sexual stereotypes becomes extremely disturbing. It helps to illuminate how destructive a force racism was in American society. Jesse is only able to understand sexual energy through race and discrimination. When he demands his wife to accept him as a man of color would "do her," it is a chilling statement.
There is little redemption in Jesse, and much in way of condemnation. His impotence sexually is reflected in a moral impotence that cannot embrace that which should be. The effect on the reader here is one in which the destruction of racism and discrimination is seen from the point of view of the perpetrator. In this, Jesse becomes victimized, something brought out by the story's ending:
He [Jesse] thought of the morning as he labored and she moaned, thought of morning as he labored harder than he ever had before, and before his labors had ended, he heard the first cock crow and the dogs begin to bark, and the sound of tires on the gravel road.
In ending the story with Jesse's narrative, the effect on the reader is one in which there is no resolution for Jesse. Racism and discrimination have made him one in which sexual relations with his wife is "labor." He is unable to even achieve the sense of release with a resolution, rather "before his labors had ended," his attention is divided and diverted once again. The condition of racism that Jesse had appropriated in his own psyche is one that gives him no release. In developing this narrative through Jesse, one has a deeper understanding of what racism and discrimination does to all members of a social order.