Several years ago we lived next door to Coptic Christians, the husband was from Cairo, the wife from Alexandria.
They stated that Coptic Christians were the "real and original" Egyptians and that the "others who live in Egypt are all Arabs, not Egyptians." The couple seemed to convey a sense that they were of a higher class and better ethnicity than "other Egyptians."
Still they were very gracious to all local Americans. They also had friends visit from Egypt and sometimes their visiting friends were dressed in Muslim garb.
It stems from a feeling of having their country stolen from them by Muslim conquerors and squatters, which is in fact what happened.