I am reminded of my review of The Cross and the Crescent:

it puts the emphasis on the mutual attitudes between the existing peoples and cultures and the expanding Muslim empire. However, I want to highlight what the attitude of the Byzantine empire towards Arabs was before the birth of Mohammed, because those attitudes are with us still today and have nothing to do with Islam

And the Ratzinger goes and quotes a late Byzantine Emperor's polemic with a Persian. As Quentin points out, it is unlikely that a man of Ratzinger's intelligence hasn't chosen his words carefully for calculated effect.

Those whom the Gods wish to destroy They first make mad. — Euripides