It's the same principle, neighborhood militias don't work because the escalate and retaliate too far. Just as players do. Law is meant to bring less emotion and more objectivity. Whatever reasons you would agree that Wild West justice doesn't work applies to player policing. And the leagues aren't immune to going too far, just as our system of justice can be broken too. It's just a vastly superior model of rule enforcement than self policing through violence, intimidation, and retaliation.