Also the presence of an executive part of the government which enforces law. If that is missing, the justice system is broken just the same. I don't understand

Also the presence of an executive part of the government which enforces law. If that is missing, the justice system is broken just the same. I don't understand why often we find it unfair when mob justice is administered (and it is unfair) but we don't find unfair that the police refuses to administer justice.