What are Reginald Rose's intentions behind the play Twelve Angry Men?

It's difficult to gauge the precise intentions of any artist, but in the case of Reginald Rose in Twelve Angry Men we can make a reasonable surmise. One possible intention could be to lift the lid on the American criminal justice system to expose its inner workings. The jury system is one of the cornerstones of that system, and most of us like to think of jurors as engaging in impartial, thoughtful deliberation purely on the basis of the evidence presented to them.
Yet in Twelve Angry Men we see that this high-minded ideal is notable by its absence, at least initially. Juror number 3, for example, is a racist bigot. He's made his mind up that the defendant is guilty, not on the basis of the evidence, but simply because he's Hispanic. A young man's life is at stake, and yet the jurors are only too willing to let their numerous hang-ups get in the way of doing the right thing. It's not entirely clear whether Rose is arguing for or against the jury system. But either way, it's somewhat disturbing that an innocent life is only saved because a charismatic individual is able to persuade the other jurors of his innocence. It's largely a matter of conjecture, but perhaps Rose is asserting the primacy of the individual over the collective in society.