Uh... there actually are.
We'll disregard the ancient rules supposedly written by deities, mostly because they're not sufficient to cover the needs of any society within the past two thousand years.
In more recent ancient history, there has been the divine right of kings. Under such a system, kings are exempt from laws because their authority is absolute, generally held to be originally granted by a deity and passed down through a bloodline (unless the ruling family fell out of favor and a new military victor gained the deity's favor, which was obvious due to that victor's victory).
There have also previously been separate rule sets for peasants and nobles, and to an extent those are still in effect in places where a society's caste system has entered its legal structure.
The term I use, "rule of man" is a more general term for a system where an individual (or group) use their sense of justice to override written rules, effectively turning every case into a battle of celebrity. That's effectively the case in rural India now, where old village councils hand out arbitrary judgments based on their whims and local politics, often resulting in harsh sexism. The core problem with any "rule of man" system is that a human lifespan is usually too short and too narrow a perspective to apply a widespread fair justice. There are a few exceptions, but it is not a reliable system.
In contrast, "rule of law" means that the law is written to be the rule. Before someone acts (as in this case, before accessing a system without authorization), they can go read the laws and find out what's legal. They can ask a lawyer for advice if needed. At no point is their fate ever left up to whether someone else thinks they're guilty or not. They can decide their own fate.
The downside to rule of law is that most laws aren't written perfectly. They don't cover every situation perfectly, and society's values change. To resolve that, the court has the ability to interpret the laws to a certain degree of freedom, but the vast majority of the law is still already written specifically, and case histories are usually public, so a judge does not need to rely on his own narrow perspective unless the dispute is an entirely new situation. Even then, parallels are drawn to previous similar situations, so we are relying as little as possible on the judgement of one person.