Give me the long answer: I'm curious to hear it.
Oof. That's more like a book than a message board post but I will try. It will be extremely abbreviated. Sorry.
The U.S. and Japan were warring economically prior to Pearl Harbor. Pearl Harbor turned the war of words and sanctions into a shooting war. Japan's invasions in Manchuria and the Pacific islands threatened the U.S. economically and militarily. The well known island campaigns and naval battles followed. (The battles I've studied most closely are the big naval battles at Midway and Leyte . . . love the "crossing of the T" in Leyte Gulf . . . and Guadalcanal/Iwo/Okinawa.) After the U.S. was within airstrike range of mainland Japan the decision was made to apply enough pressure to the people and economy of Japan to make a surrender by the ruling regime palatable. No one really wanted to have to invade Japan. This was the alternative. The pressure worked. Japan surrendered. I have little doubt that if we could have obtained the same result (the end of the ruling regime and the removal of Japan's military threat) with killing fewer Japanese citizens we would have done so.
If you're interested in my opinion, I think the ends did justify the means (firebombing and nuclear weapons). The Japanese government initiated the shooting war and seemed quite willing to continue it through a land invasion. That would have been enormously costly in US lives and money. In this type of war I am more comfortable with the enemy paying that price.
Anyways, are you arguing that the goal of the war in the Pacific was to kill as many Japanese people as possible . . . just for the sake of killing them?