It seems to me the relevant difference is that in blackmail one or both parties end up worse off. So a group of individuals who blackmail each other tend to get poorer over time, compared to a group that successfully deters blackmail.
It seems to me the relevant difference is that in blackmail one or both parties end up worse off. So a group of individuals who blackmail each other tend to get poorer over time, compared to a group that successfully deters blackmail.