It is the parents responsibility to set rules and guidelines, to teach right from wrong and to make sure the child knows the difference between good and evil. Children especially very young children cannot be relied upon to learn these ideals and values on their own. Very young children have minds that are very pliable and easily led and that is why instruction from responsible parents is key and important.
Why do you think they want every child in Pre-Pre School?
Relying on parents who have no moral values themselves, don't help much either.