You may be right, I don't know enough to say. Perhaps it was wishful thinking in retrospect. (He said it in the 1960s when the nuclear genie was definitely out of the bottle and causing major headaches for everyone.)

There is a 1950s fictional film by Akira Kurosawa called "I Live in Fear" which tells the story of a man driven mad by fear of radiation from a nuclear war. For better or worse it is easy to forget now what a catastrophic thing the introduction of the bomb was for everyone.