I think this also has to be considered in the context of an ongoing cataclysmic war encompassing the world where whole cities were being destroyed and of course they were developing a weapon to destroy them faster. Today, WWII is that long ago thing that lasted for a few years and then it was over. Soon the veterans and the Holocaust survivors will all be dead. To anyone then, a lot of things probably didn't seem as important. A lot of people reacted to the atomic bomb once it was public as the impending end of the world, too. So the scientists who knew about it first probably had their attitudes affected.