> This whole meme is bullshit, and comes from a post-apocalyptic novel where it's used as a justification to murder a prisoner of war (in context). Most people don't know its origin though. They just repeat it because it sounds "truthy" if you don't think about it very much.

The meme is at least a few months older than the book, and most likely actually comes from a simplification of https://en.wikipedia.org/wiki/Strauss%E2%80%93Howe_generatio...