I lived in Japan, and have been to Hiroshima a couple of times. I never encountered any bitterness or resentment as an American, though the Japanese are pretty reticent about their emotions. By and large, it seemed that WW2 is regarded as a terrible period where “mistakes were made, and terrible things happen in war”. The high school history textbooks I saw covered WW2 in a couple of pages, one of which was invariably a photo of a mushroom cloud. I suspect if we’d nuked other countries, this wouldn’t be a big deal… just another horror of modern warfare.

FWIW, they started it, we finished it. Japan got off easy, compared to what it would have been like if Operation Downfall had gone on.