What is the significance of the little girl in the RED coat?

she was in the movie schindlers list. This one child is a symbol of all the 6.000.000 victims, exposed to ruthless slaughter. The little girl in the red coat footage gives a feeling of hope. You think that she may be able to get away, that she has a chance. But then you see her later, and she is dead. She has already been killed, and you feel the despair and a lot of anger towards these Nazis. How could they kill something so innocent?