Why do they deny and deform the Christian and Church history in school books?

Fr. Dr. Peter Madros talks about the history of Christianity and the church, and how the history school books (and in other curriculums) in the Middle East and all the Arab countries are either denying the Christian history and presence or deforming the history of the Church and portraying it in a very negative way. Furthermore, even in some Western countries, many people and maybe officials are trying to deform the history of the Church!

deformChristianChurch