This world is just full of “luck” mechanism. A person born privileged, educated parent can never be comparable with someone who was born in a war-torn country.
There has to be a mechanism at work to make life at least equal, without the afterlife mechanism in place, death are just death, and killings doesn’t matter that much. Of course justify it however we want by using the law, but the heaviest punishment for a person killing a whole human race is death, slowly or quickly, it doesn’t matter. What matters is in the end death of thousands could never be justified with one simple death.
In a world where society doesn’t believe in the concept of afterlife, there is no long term consequences of doing bad. After all human life is fragile and doesn’t last very long so the maximum amount of punishment a person can receive is his total lifetime given that he doesn’t commit suicide in the process.
I’d hate to say it but the idea of “you reap what you sow” only works in the case where there is no ambiguity in cause and effect. There is so many variables in play that are completely out of control. It’s probably conceptually possible at least according to what I believe is true to categorise people just by using this expression. If you believe that this is true then you are probably very most likely a part of the people that are considered to be “lucky”.