Why is this special? The Japanese killed ~7 million Chinese, 0.5 to 1 million Filipinos, 500k in Korea, you can keep adding them up. Then Japan loses 0.2% of all their atrocities and it's the worst thing ever? No, it's not the worst thing ever, not even close. Sure, we'd all like it to never happen again. But if I had to pick one thing not happening again I'd pick saving all others that died in WW2 over this one incident.

https://www.youtube.com/watch?v=DwKPFT-RioU

There's also the argument that it saved more lives than the deaths it caused. The same can not be said for Japan's atrocities.