William Faulkner has carefully constructed the story so that numerous characters play equally significant roles. As the barber, Hawkshaw, acts as the voice of reason in opposing the attacks on Will Mayes, it can be argued that he is the protagonist. Even though the story concerns the fate of Mayes, who is African American, most of the plot involves the white townspeople whose actions have differing, and significant, effects on him—ultimately ending his life.
Because McLendon is the main person who pushes ahead with this racially motivated violence against Mayes, he seems the most obvious choice for the antagonist. At the same time, the townspeople might not have attacked Mayes if they had not perceived there was a cause for alarm. Faulkner implies that Minnie Cooper is responsible for starting the rumor that sparked the violence, so a case could be made for considering her the antagonist if Mayes is the protagonist. Her central role also makes it possible to see her as the protagonist, in the position of anti-hero.
Because so many people in the town support the persecution of Mayes and so few oppose it—at least publicly—it seems logical to consider the entire town, standing for racist society, to be the antagonist.