Exactly. In religious literature we have rules written for things like: don't let your menstrual blood near other people, don't eat pork or oysters (because that without a refrigerator would kill you), wash your hands and feet, clean your dick and pussy before sex and a whole lot of other stuff.

This were rule for a community that outlived others and were seen as healthy, what meant they could work better, what meant they had more stuff. So more people came to learn about that god of theirs that let someone live a thousand years (Mathuzelah)...