I think the general anxiety of the 1960s - '70s spawned our interest in the living dead. When people worry about the end of their world, they need a safe vessel for all their fears. Zombies provide that vessel because they're 'safe.

...because I'm sure that as soon as things really get back to "normal," once our kids or grandkids grow up in a peaceful and comfortable world, they'll probably go right back to being as selfish and narrow-minded and generally shitty to one another as we were.

Imagine what could be accomplished if only the human race would shed its humanity.

You can watch 'Dawn of the Dead' and still sleep at night. Try that with 'The Day After'.

The dead walk among us.

You can't blame anyone else... You have to make your own choices and live every agonizing day with the consequences of those choices. He knew this. That's why he deserted us like we deserted those civilians. He saw the road ahead, a steep, treacherous mountain road. We'd all have to hike that road, each of us dragging the boulder of what we'd done behind us. He couldn't do it. He couldn't shoulder the weight." - Philip Adler

Zombies let us explore notions of the apocalypse - no water, food, medical care, the government imploding - while letting us sleep at night.