I agree with most of your post. However, your Gettysburg comparison struck a nerve. We read about Gettysburg in school, of course, but until I visited there at about age 30 it was just old news. Once I got past the chintzy shops in town and out on the actual ground, it hit me like a brick. Picturing hundreds of men with muskets charging into cannons loaded with the equivalent of shot . . . And the aftermath, wounded men lying untended for hours, days afterward. . . And the people charged with cleaning up later . . .
Yes, they didn't have nuclear weapons and fewer people were involved, but it was the great disaster of the time.
BTW, when I was young, I read a book in the church library about 5 or 9 ( can't remember) people who survived Hiroshima and Nagasaki. I think that was the title of the book. These people were in Hiroshima for the first bomb, then got to Nagasaki just in time for the second! And lived - at least for a while.