Postcolonial literature critiques ideas that are prevalent in colonialist literature, such as the theory that colonialism is good for the colonized because the white colonizers bring "civilization" and Christianity to native peoples. Postcolonial literature represents the point of view of the colonized and pushes back against narratives that treat white people as superior and darker-skinned people as childlike or dangerous.
Heart of Darkness is postcolonial, even though it is told from the point of view of a white colonizer, because it is a critique of the harm done by the white colonizers in the Belgian Congo. Conrad dispenses with any idea that the Europeans are bringing good to the natives, presenting that instead as a myth and lie that is used to lull the women at home into thinking colonialism is ennobling.
Instead, Conrad presents Kurtz as the true face of colonialism. Though he starts out with noble aspirations, Kurtz quickly becomes a tyrant who encourages the natives to treat him as god, who kills them when they present problems, and who will stop at nothing to get the ivory the Company wants. His philosophy moves from benevolence to "exterminate all the brutes," which to Marlow's mind represents the real attitude of white people toward the African natives. Kurtz's final words, "The horror! The horror!," sum up what colonialism is in Conrad's view.