Hiroshima, Nagasaki in ethical perspective of nuclear bomb creator

"Out of curiosity, I have always thought about the minds of scientists working 76 years back in 'Manhattan project' then in 1948 and whose labor was materialized in less than a month time after 'Trinity' test, into a man hunting arsenal causing massacre at large in Hiroshima and Nagasaki on 6th and 9th August 1945, culminating into the last bloodiest scar for humanity to remember for generations, if they do not learn any lesson from.

From their statements, some being quoted below for easy reference, one can easily conclude their utter frustration from this outcome with a collective sense of regret." 

--Author

(Storyline: Second world war/ Nuclear bomb/ Aesthetic and ethical judgement)

Life is lot more fragile than we think. So you should treat others in a way that leaves no regrets. Fairly, and if possible, sincerely. It's too easy not to make the effort, then weep and wring your hands after the person dies. 

--Haruki Murakami 

J. Robert Oppenheimer: 'We have made a very grave mistake', and 'in some sort of crude sense..the physicist have known sin.'

In a famous quote about his meet with President Henry Truman, he has said then, 'Mr. President, I feel I have blood on my hands.'
Well, then he was referring the future too.

Henry Wallace, then the Vice President, recalls about him in his diary, 'I never saw a man in such an extremely nervous state as Oppenheimer. He seemed to feel that the destruction of the entire human race was imminent.'

Later he vocalize his fear by saying, 'the people of this world must unite or they will perish.'

Reminiscing his earlier days while working in Los Alamos Laboratory, 'To me (the task at hand) is primarily the development in time of war of a military weapon of some consequences,....concern was as if to save the civilization.'

Perhaps when he referred through his famous quote of the Gita after the Trinity test:   'I am become death, the destroyer of the worlds,' ..was perhaps pointing his concern for humanity in posterity.

Albert Einstein: He did not play a direct role but his discoveries did and he was in regret for the letter he wrote to Roosevelt . 'Had I known that the Germans would not succeed in producing Atomic bomb', he said, 'I would have never lifted a finger.'

In 1954, 5 months before his death, he has said, 'I made one great mistake in my life ..when I signed the letter to President Roosevelt recommending that atom bombs be made.'

'Politics is more difficult than physics', was the answer of Albert Einstein when he was asked, why one can discover the atomic power and not to control it.