Re-watched it recently. Ending of trial didn't live up to hype that movie created

When you watch trailer and then movie and Brad Pitt is hyping up like "We will bring them down. Uncover it all" you get the feeling that not everyone will finally know the truth about all the abuse all those children suffered from the hand of state. And it will be all so scandalous that heads will roll.

And then that one prison guard confesses on trial and.... nobody cares. Like at all. No press anywhere. And that court room if freaking empty when Robert De Niro is giving his statement. There is like 5 people in there and all other seats are empty. I almost felt sorry for those 4 main characters.

What was Brad Pitts plan? If that one prison guard would not confess out of nowhere because he felt sorry. If he would be like: "Nope, noting happened". Then what?

I thought Brad would try to track other people who were inmates there and get them to speak. But no. Ending was kinda underwhelming.