I don’t understand why we had to keep testing over and over and over. And then expect there to be no problems with fallout. USA #1!
Are those separate questions or the same question? We have to keep testing as the bombs are improved. Computer modeling can only do so much.
We didn't know anything about the effects due to exposure to radiation. I don't find it surprising at all that everyone associated with the earliest nuclear testing ended up having greatly shortened lives due to cancer. (Which includes Dr. Marie Curie who "discovered" radiation).
After the Cuban missile crisis, the Limited Test Ban Treaty was signed which prohibited anything other underground testing. Someone was thinking about it, at least by 1963.
The Comprehensive Test Ban Treaty is another matter altogether. That would be folly to sign & ratify and maintain a defensive nuclear arsenal. (The watchdog organization for that as yet unimplemented treaty is the site where this video came from).