When a child is sacrificed by adults, technically it means doing the ultimate evil(a developed being with free will chooses to do ultimate harm to an undeveloped being) and thus it "proves" that no constructive forces can block doing this ultimate evil. If there would have been a constructive force, aka good side, it would do everything to stop this, because nothing else trumps the evilness of the act. Child sacrifices, in simplistic terms, are basically constant test runs to prove good god doesn't exist. This act rationalizes everything else what can be done to humanity.