Aliya Summary: The Torah prescribes capital punishment for one who worships Molech; a form of idolatry which required human sacrifices. The Torah also describes the punishment which will befall the nation if they neglect to punish Molech worshipers.
An interesting twist is presented here. If society doesn’t have the moral compass to understand the gross immorality of human sacrifice, G-d will punish those that perform it, and those that don’t punish the perpetrators. Although it’s not an active sin (one that requires action), the acceptance it indicates is enough of an evil to warrant severe retribution.