The denigration of Coptic Egyptians really began under Nasser when nearly all were deprived of jobs in the government sector and in Nasser’s Arab Socialist Union. There were a few Coptic fellow travellers like the anti-Semite Boutros Boutros Ghali, even while no new Coptic churches were allowed, and the attacks on Christians which began in Upper Egypt at Assiut and surrounding area were allowed without interference. Since then, tens of thousands of Copts have emigrated to Australia, Canada and the United States, where, unlike Muslim immigrants, they can be depended upon to make excellent citizens.
I can't dispute your point. Maybe it got a lot worse at that point. But Egyptian religio-ethnic tensions were so bad way back in 1910 that even Theodore Roosevelt got peripherally involved!
If you're interested in this sort of thing, maybe you'd enjoy the brand-new biography, "Colonel Roosevelt," by Edmund Morris. I just got it for Christmas and found it quite a good read. Moreover, speaking of Boutros Ghali, the man who must have been the "original" Boutros Ghali was assasinated by Egyptian fanatics in 1910.