[Suhiir]

There was a rather steep and expensive learning curve when it came to the side effects of both nuclear and chemical weapons. No one had a clue what the long-term effects would be and there's no way to study them until you actually have someone with them. They certainly didn't have access to modern research techniques and devices.

Keep in mind during WW II people didn't take noncombatant casualties into account nearly as much as we do today. One may as well feel morally outraged about Roman slavery as WW II attitudes.