This is what I came here for. Like you said, the rule is about how you treat others, and intentionally doesn’t account for how others treat you. As was already said, lots of religions have similar rules. They also have parallels to “lead by example,” “turn the other cheek,” “vengeance is mine, sayeth the Lord,” “judge not lest ye be judged.” All of these are guidelines for community cooperation and fellowship. There will always be people who go against them, but if the overall community adheres to them it’s generally in a better position to be stable and succeed.