The main point is that anything repeated again and again and without sanction can seem to be "normal" and acceptable behaviour over time. Such is the case with the villagers, who accept human sacrifice as a 'necessary evil' simply because it is a ritual entrenched in their culture and 'has always been that way.' No moral issue is even raised as to the right or wrong of such a practice since reference points indicating otherwise have long been lost.
When asked about her motivation to write such a disturbing tale, Jackson stated:
"I hoped by setting a particularly brutal ancient rite in the present and in my own village, to shock the story's readers with a graphic dramatization of the pointless violence and general humanity in their own lives."
Unfortunately, such overpowering pressure to conform to the status quo is not just a matter of fiction or the ancient past. Jackon's story is ever relevant, challenging the reader to reconsider present society's value systems and if they are really 'valid' after all.