I think that part of the reason they have to be like that is to fairly represent. The need for this is there to try to provide opportunity for truth to come to light (or should, ideally). It helps prevent and dissuade false accusations and personal bias to affect the case. We read the story now after it has unfolded for the most part, but at the time of accusation no one except those directly involved know the truth about the situation. I can't imagine it always comes with a clean conscience either. I'm not defending the guy at all, just trying to explain the importance of fair representation with as minimal bias as possible. If we didn't have that in our court system, as broken as it is, it would be a lot worse.