Luckily you outgrow it, the same as when you read about German atrocities, and then get over that too. But it's quite a shock the first time you read about that kind of thing.
It's remarkable to me how a country like Japan can change so much in the course of a generation or two, and how friendly we are with Japan now. It's quite a testament to America, I feel, that we could forgive so quickly. I know there were political reasons for becoming an ally with Japan during the cold war, but still.