World without killing cannot survive if it is a land for survival. We call it food web or food chain. According to me this film so far concerned about 'killings' which is also a major Buddhist philosophy- speaks not to. If a lion or tiger decided not to eat flesh, first it would die, then the preys without any control of population would multiply and eat up all the greens led their own extinct, which is happening in the case of Human. To delay the extinct man started to make food for himself through cultivation, animal husbandry, aquaculture etc. Thus extinct is unavoidable for every organisms if it over populated. So Killing can be justified if it is not an 'unwanted' but for bare survival.