Rule of law is not about whether the outcome in a particular case is good or bad, or whether a particular law is good or bad. It's about whether the outcome is arbitrary, and whether you have recourse when the outcome does not align with the law as written. When the state can arrest people and imprison them (or release them) arbitrarily, you don't have rule of law.
Does that mean if the law says the police have arbitrary discretion to decide who to imprison, then the outcomes align with the law as written and you still have rule of law?
How about if the law is written so strictly that everything is an offense, such that it's impossible to enforce on everyone, and you choose to not enforce it against people you like? Any case where it is enforced, you can still point to the law and say the outcome aligned with it.
And what if the law unequivocally says a certain group of people are slaves, is this justified simply because the outcome is not arbitrary and there is a codified rule of law? Whether the law is right or wrong does matter.
The relevant metric is whether you can reliably predict the outcome of almost any interaction with the government. If government actors are constrained by the law, you can reasonably predict what they will do. If the law is just a fig leaf, you won't be able to predict their behavior. No society is entirely autocratic or entirely governed by the rule of law, but they tend to cluster at one end or the other.
If I can predict that almost any interaction with the government will end in my destruction, that is not a sufficient standard of justice. The problem is not that chinese citizens can't predict the behavior of their government.
Rule of law is necessary, not sufficient, for justice. You cannot have justice if you do not know what behavior will get you punished, and you cannot know what behavior will get you punished if the government can act arbitrarily with impunity.
Edit in reply to below: the issue in China is precisely that the government's response to criticism is unpredictable. If Xi Jinping criticizes Chinese policy, that means a new policy is now in place. If a random guy on the street criticizes Chinese policy... maybe he'll be fine? Or maybe not. Depending on where and to whom he says it and how nice public officials are feeling that day.
And the problem with China is not that it's lacking rule of law, but that the laws are unjust. It is easy to predict what will happen to you if you criticize the government.
> So if the lady in China went down to the police station, called a lawyer, and got released 6 hours later, everything's ok?
If China elected Xi in a free and fair election, if they developed faster than light travel and clean fusion power then everything would definitely be ok!
But here in the real world I'd like to hear the story of this hypothetical Chinese lady who got a phone call, let alone a lawyer. Was she rich and a well connected communist party official? Or more likely this is just a made up happy fantasy, like warp drives?
It also scares me that so many people are willing to say, "At least we have the rule of law unlike that video." If the end result is exactly the same, that's scary.
But also, as long as somebody can show you horrendous atrocities happening elsewhere, you are willing to let minor local infractions of the rule of law stream by? Just show orphanages getting carpet bombed and it's not a big deal if we mistreat immigrants. Show immigrants getting mistreated and it's ok if we arrest homeless for sleeping in the park.
When I was young, Germans were bad guys. Then Russians. Then Chinese or North Koreans. Back to Russians. Or Mexicans. Or Canadians. Fight for justice in Africa. Feel safe and secure in your own benevolent democracy.
Watch two videos of the exact same behavior and excuse one of them because it is happening in a place that practices the rule of law. Condemn the other because of their voting system.