Political preconceptions
It's worth remembering that while the U.S. was agonizing over whether or not civil defense was just "the living envying the dead," all over the rest of the world, comprehensive civil defense was, and in many cases still is, policy.
This included not only China and Russia, adversaries who apparently considered a nuclear exchange survivable, but other benign and even neutral Western nations like Switzerland or Sweden, often held up as examples of how to run things in the U.S.
What do they all know that we don't?