We were teaching children to kneel under their desks and place their hands behind their neck - Duck and cover! I was one of those children.
Why?
Because there is not much else one could do.
It gave people something to think about that could help them emotionally handle the thought of nuclear war.
Same thing about the bunkers. People feel better if they can do something (anything) when faced with the risk of a terrible event they have no control over.
By being given a tiny bit of control (duck and cover) or six feet of compressed dirt in your backyard, it can help.
I can only speak for my family and my experiences growing up in the cold war -- no one had fantasies of surviving. A bunker was a place to die with your family.
