I've had a theory stewing in my head about this whole thing for a while - I think that the court itself, gallery and all, is a "monster", one that preys on recently defeated magical girls to gather magical energy through their "punishments".
This is sorta baseless but my thought is: this monster has some sort of limited mind control magic, allowing it to assert itself as a part of magical girl governance - perhaps with every magical girl "defeated" inside it/"punished" by it, its effect/establishment grows stronger. Attempts to directly and physically fight and defeat it have failed so far - perhaps the judge (appears to have been revealed as the protagonist's older sister this chapter? Maybe? the hair is a little different, but it's the right color and the eyebrows are similar, but on second look they seem too different so I think I'm just crazy), the prosecutor, and the messenger(s) are all magical girls who attempted to directly attack the court, and ended up ensnared by it and put into one of its "roles".
This would mean the true goal of the protagonist isn't just to defend magical girls, but to defeat this court "monster" covertly by playing by its rules, stealing away its "food" to weaken it and potentially free the magical girls trapped by it (including her sister, if the judge is her... notice the protagonist focuses on the judge when she says "the defense also thinks big sis is not to blame"... but that could also more likely be her subtly lashing out because her own sister was ruled guilty despite being innocent in the past, setting up for more protagonist backstory later)
Of course, this is complete mix of hopium & copium and probably isn't all that likely but if something like this turns out to be true maybe it'd save the manga for some of the people so riled up at the injustice/absurdity