I think this gives far too much weight to the imperfections of individual people while ignoring the entire purpose of having a judicial system in the first place.

Of course judges get tired, jurors get bored, attorneys vary in competence, and individual people bring their own biases and prejudices into the courtroom. There is no mechanism capable of removing human judgment from a system that necessarily requires human judgment. But that does not make the process a series of random coin flips.

The entire point of procedural rules, evidentiary standards, constitutional protections, appellate review, sentencing guidelines, jury instructions, disclosure requirements, standards of proof, and the adversarial process is to constrain individual discretion and make the outcome less dependent on any one person's mood or personality. They don't eliminate human error; nothing could. They create a framework within which human beings are required to operate.

And there's an important distinction between saying “the system can produce unjust outcomes” and saying “the system is fundamentally arbitrary.” The first is obviously true. The second doesn't follow from it.

If the judge has a bad day, that doesn't mean the law disappears. If a defense attorney is incompetent, there are remedies for ineffective assistance. If a judge makes an error, there is appellate review. If a prosecutor violates the rules, there are consequences. If jurors disregard the law, the verdict can be challenged. None of these mechanisms are perfect, but they exist precisely because we understand that the people operating the system are imperfect.

My own experience actually illustrates this. I went through the system, I was guilty, and I deserved the sentence I received. I don't remember the courts being perfect or every person involved being perfect. What I remember is that there was a process, there were rules, there were competing sides, and there were people whose job was to make sure those rules were followed.

That's a much more accurate description of the justice system than “100 coin flips.” It's a human institution deliberately constructed to put as many constraints as possible on human fallibility. Sometimes those constraints fail. Sometimes they work remarkably well. The fact that they cannot produce perfection doesn't make them pointless.