Not killing children is a modern thing. Humans killed heirs and children of important people all the time. It's how they maintained power. Society evolves...It's now seen as punishable act. There were lots of behaviors that were once ok, that are now looked down upon. shyt look at drunk driving. It used to be considered a folk crime, rarely punished...Now it can fukk your life up.
And the reason we don't use sniffing to identify people, places or things, is because we've named them. We've identified them as good/bad/indifferent. Wild animals don't have that luxury, and there's nothing that has forced them to evolve from that behavior.
People trying to influence someones behavior based on their own personal set of rules/regulations are simply just narcissists. Eat meat...Don't eat meat...Leave me alone.