To say simply that Orwell rejects imperialism in this essay would be to disregard its many nuances, although Orwell is clear that when serving as a policeman in Burma he felt the British regime to be "evil." There are many more interesting theses you could derive from this essay than...
To say simply that Orwell rejects imperialism in this essay would be to disregard its many nuances, although Orwell is clear that when serving as a policeman in Burma he felt the British regime to be "evil." There are many more interesting theses you could derive from this essay than the rather obvious "Orwell feels that imperialism causes distress to native peoples, oppresses them, and keeps them in lives of poverty." We might point, for example, to the early indication that Orwell believes imperialism to be almost inevitable in one form or another. As a young man, he says, he knew that the British empire was a terrible thing but not that it was in fact much better than "the younger empires that would supplant it." What is Orwell suggesting here? He is suggesting that imperialism of an institutional sort has gone on for many years. According to Orwell, the British empire is potentially a lesser evil than a new ambitious imperialistic leader or regime unused to ruling status.
Orwell's central thesis on imperialism in this essay, however, is debatably summed up in this section:
Here was I, the white man with his gun, standing in front of the unarmed native crowd—seemingly the leading actor of the piece; but in reality I was only an absurd puppet pushed to and fro by the will of those yellow faces behind. I perceived in this moment that when the white man turns tyrant it is his own freedom that he destroys. He becomes a sort of hollow, posing dummy, the conventionalized figure of a sahib. For it is the condition of his rule that he shall spend his life in trying to impress the "natives," and so in every crisis he has got to do what the "natives" expect of him. He wears a mask, and his face grows to fit it.
For Orwell, then, imperialism is not only evil, it is self-defeating for the empire if the goal is to be in absolute control. As an agent of the British Empire, Orwell felt that the power was in the hands of the people he was supposedly controlling: imperialism is a facade concealing the truth that, in any situation, the majority will rule. Humiliation and peer pressure effectively drove the young Orwell to do something that was the very opposite of what he wanted to do. Orwell's essay is an explanation of how his own understanding of imperialism became more nuanced after he recognized the damage it does not only to the subjugated, but also to the supposed subjugators.