No it was built by people like you and me. You know those useless people in your office? They're also in the judiciary. You know that stupid policy that while it may have some uses, leads to other bad outcomes but no-one can be bothered to fix? That's also present.
Is there an alternative?
Unfortunately politicians don't want to get involved, and by and large the populace don't have any dealings with the courts.
Yes - clearly the justice system has been coopted and corrupted and "social justice" is one of the expected and observed outcomes (similar but different than mob justice - which is also another expected outcome when you can't rely on actual police/judiciary).
The resolution to all this is to restore faith and trust in our formal justice system - and there are folks fighting for that also.
It is the lack of religion, because religion is exactly what would fill this gap in the minds of people from seeing injustice. Maybe the earthly judges failed, but I don't need to be cruel and punishing because the criminal will get what's coming for him in the next life.
It doesn't even matter if this argument is true or false, and if there is another life and judgement in it. That line of thinking clearly keeps people more civilized. Here in the present, in an objectively observable way that even complete atheists could compare.