Pushing responsibility upward and allowing escalation should end at some point. The administrators should just repeat what the teachers said, and tell the parents that the only way to get better scores is to invite the child work harder for the next test. It's really that simple.

Now, if even the administrators can't do that then someone in the city government, state government or federal government should be able to draw the fundamental line whether the purpose of schools is to give students A's or grade them based on their actual knowledge and make the student responsible for his/her own grades.