This is the whole basis of the adversarial justice system in the US, and other common law countries. The Judge is a neutral party, and only hears what the parties put forward. Each party is expected to act in his own self interest and present the best case that they can.
I have always thought that this was a failing of this system. Those with more resources naturally can present a better case, if only because they can hire lawyers, who know the minutae of law better than anyone else, simply because that's their job. The litigant in person doesn't, presents a terrible and throws himself at the mercy of the court.. the court which is just, and fair, and only hears what the parties put forward themselves.
Compare this to the inquisitorial system, where the Judge actually investigates, and takes a far more active role in the system, rather than simply sitting back and being a neutral party.
Of course, that also opens up the possibility that the Courts will be corrupt, and that the Judges will persue arguments based on their own prejudices, and so on..
It might be, as in life, that poor people are simply fucked. *shrug*