the bible also sez get ur drinking water _upstream_ from ur latrine, so of course all religions evolved thru natural selection;-) in a pre-literate world how do u pass on such survival tips? oral traditions wrap them in mnemonic narratives, and how better to enforce their practice than gods' gonna zap u (b4 lightning was understood, which wasn't all that long ago*) if u don't?-)
the downside is when those narratives are elevated to blind obedience/conformity...
*like the response of an undamped resonant system to a step function: we're still oscillating to the introduction of fire ffsake...prometheus caused global warming;-)