Another important Tisha B'av lesson, our mourning and lament have a profound effect. We stay the Divine Hand, and, hopefully, inspire our souls. Catharsis is a pedagogic device. Destruction, debacle, disaster is a phenomenon beyond simple punishment. The worst sin one can commit against himself and Hashem is betraying one's role and place in Jewish destiny.
Destruction is destiny denied.
Esther heeded and salvation resulted. She intervened and victory was snatched from the jaws of defeat. Josiah was informed by Jeremiah what his role was, and he muffed the assignment. Josiah intervened and snatched defeat from the jaws of victory. We don't have the benefit of a prophet nearby to inform us of our role.