Sorry, but, That wasn't Einstein. Enrico Fermi, one of those 'inferior' Italians was the man who did the background physics for the Bomb. the work was then pushed forward by J Robert Oppenheimer, who was later vilified and forbidden from looking at his own work, for being soft on Communists. (He wasn't, he just didn't suffer fools gladly.)
Einstein was worried about other things. Mostly in the Cosmology and Unified Field areas of physics.
Fermi, in his turn came to the US to escape Mussolini, just as Einstein did to escape Hitler. He was mostly working on Nuclear interactions. All carbon moderated reactors are the results of his work.
We seem to benefit from the evils of others.