Most blacks do not want to go to Africa during the colonization movement because they had been born in the United States and had little in common with Africans. As you can see Africa and United States were different if I'm not mistaken the U.S used Africans as slaves back in the day so that could probably explain a lot.
One argument was that if the U.S. solely did a "test demonstration" of the atomic bomb, versus dropping it immediately on Japan, Japan would see the devastation of the bomb and would surrender on their own will without suffering huge losses.
