The statement that best explains why the public school system created during Reconstruction was both a success and a failure is:
It allowed all southern children to get an education, but since the schools were integrated, many white children did not attend.
This statement highlights the success of the initiative in providing education to a broader demographic, including previously marginalized groups. However, it also points out a significant failure: the resistance from white families to integrate schools, which limited the overall effectiveness and acceptance of the system.