I reiterate:

Imagine a human in complete isolation — no parents, no family, no friends, no community.

Descriptions of the individual in society simply prove the point. And since there is no such thing as a single, isolated, unrelated human being, it follows that we’re all in this together. Every action that harms another harms all, every action that heals one heals all, and those who forget this basic fact are dangers to all.