There's no doubt about it: "Portrait in Georgia," is a gory and violent poem. After all, when you take lynching as your subject, you're bound to include some graphic scenes to get your point across. The violence present in the poem hammers home the intimacy at the heart of violence—one body destroys another. To lynch another human being, you have to get close—close enough to smell their last breath.
By describing a woman's body part by part, the speaker has removed the personhood from it, which is a kind of violence. He's made her into an object.
Violence has changed the victim's body by emasculating it, feminizing it, and turning it white.