He writes about what it feels like to be disliked for being a European: “All this was perplexing and upsetting. For at that time I had already made up my mind that imperialism was an evil thing and the sooner I chucked up my job and got out of it, the better. Theoretically—and secretly, of course– I was all for the Burmese and all against their oppressors, the British. As for the job I was doing, I hated it more bitterly than I can perhaps make clear. The cardinal rule for narrative is to begin “in media res.” Yet Orwell violates it here. Why does he give us the back story above?

The principle of starting in medias res is not followed quite as often as one might think, but an important fact to keep in mind about "Shooting an Elephant" is that it's not so much a story-narrative as an essay, an expository meditation about imperialism and related issues. Above all, Orwell wants to get across to the reader the predicament in which he, as a British policeman, finds himself in Burma and the psychological effects it has upon him. To some extent, the action that takes place—the report of the elephant gone "must," the huge crowd of people who gather and egg Orwell on to destroy the elephant when there is really no need to do so, the shooting and death throes of the animal—conveys in itself the effects of imperialism on both "the natives" and the Europeans. But the introductory passage is used to set the stage, to provide a background, without which a British or American reader might not fully grasp the implications of the story that follows.
It is later, when the story has progressed to the point where Orwell feels trapped, forced to act against his own judgment, that he makes his now-famous evaluation of the warped, controlling effect that imperialism has on each person tasked with enforcing colonial rule. A European in Asia becomes a kind of hollow, posing dummy, "the conventionalized figure of a sahib." In Orwell's view, when the white man becomes a tyrant, "it is his own freedom he destroys."