Thomas Hardy is a British writer, and in British English, the word "curious" is more likely to be used to express "strangeness" or "oddness," instead of "the state of wanting to know more," as is the most common American English connotation. In the poem "The Man He Killed," the tone of the words "quaint" and "curious" is light, and conveys a sense of bemusement more than shock. This is all in keeping with the writer's purpose; his intention is to communicate the complete absurdity of the concept of war by approaching it with a matter-of-fact attitude of mild amazement. The contrast between the exceedingly grim reality of his subject matter in the poem and his own quiet wonderment in reflecting on it creates a vivid sense of irony, and it is through this ironic tone that the writer conveys his message. In war, you unquestioningly "shoot a man down" whom, had you met him in other circumstances, you might have been great friends with, and if you really think about it, this situation is completely absurd. The fact that the speaker uses such mild terms when considering this completely tragic phenomenon only accentuates the disconnect.