Few, if any, can answer this. I think that the ending to the diary is what helps make it such a powerful piece of literature, in general. Bringing it out as the ending to the play helps to create the sense of drama that is such a part of the Holocaust. While the ending speaks volumes about the Holocaust, it carries a sense of the profound, in general. I think that the ending reflects Anne's own maturation and her own growth throughout the diary. At a point where there is total madness in the world, one can see how the protagonist seeks to believe in redemption and in human goodness. This reflects an aspect of adolescent growth where the abstract is embraced and the complexity in the world is dissected through individual perception. The ending to the diary reflects the level of thoughtfulness and intricacy in thought that Anne has absorbed throughout the narrative. It is difficult to ascertain why the ending is the way it is, other than to indicate that Anne's mind would have continued to generate profound thoughts had the Nazis not captured her. In this ending, I think that the true sadness of the Holocaust is revealed, in that some of the most profound of thinkers were extinguished with little regard. The play's ending in this light helps to reinforce this.