Why can people still live in Nagasaki and Hiroshima after the nuclear explosion in Japan? Is there really no harm in doing this?

Suppose the earth will explode within a year, then will you still live on the earth during this year? Some people may say, hurry up and escape on Noah's Ark. Yes, assuming you can escape on Noah's Ark, and assuming there is really somewhere to go, how many people can get on Noah's Ark? In the same way, after the nuclear bombings of Nagasaki and Hiroshima, everyone knew that continuing to live there would be harmful to their health. Therefore, those who had the conditions would choose to move to other cities to live, but most people did not have the conditions. Where can the transferred people go? It’s not that they don’t understand the dangers, it’s just that living in Japan, which is an island country, where can so many people move to? Therefore, continuing to live in Hiroshima and Nagasaki is a helpless move for most people.

So, things in this world have cause and effect. We must be kind to others, whether it is as small as an individual or as large as a country. The civilians in Hiroshima and Nagasaki were innocent, but aren't the millions of Chinese people who were massacred by the Japanese invaders innocent? Nuclear explosions will cause harm to people's bodies. However, if some Japanese militarists do not face up to history and continue to cause trouble under the banner of militarism, then perhaps there will be more than just two nuclear bombs waiting for them.