Don't just assume that it applies to the wild nature, the foundational rule at the core of society built by the Wisdom Species also follows this simple guideline.
"Survival of the fittest".
It's the one and only truth that life, being part of nature, can't resist. Anyone who defies or questions it will be swallowed by this brutal truth.
If you want to survive in the harsh natural environment that has no regard for life, you must fight. Eating or being eaten is a common occurrence. The boy's father and neighbouring uncles raise livestock and hunt birds and beasts in order to feed the boy and other children, in order for everyone to live happily.
The boy didn't say it out loud, but his sharp mother sensed the shapeless questions and fears stirring in her son's heart.
"Is living such a sinful act?"
The question brought an unprecedented sense of terror to the boy, unable to find an answer, a way out. The despair made him burst into tears, seeking help from his mother.