Those saints aren't "Anglo-American"...St. George was from Lydda (Palestine), for instance, and last time I checked, St. Mary was not from either England or America. You're confusing the language with the people, but Coptic antipathy towards Arabs is something different than just that. There is no real reason for Copts to avoid using Anglicized forms, as the English never cut their tongues out for speaking Coptic, never burned down their churches or destroyed their monasteries, never forced them to convert to Islam, never kidnapped their daughters or raped their wives, etc. It sucks, especially for the millions of Christian Arabs, but Islam has been souring the world on Arabs and Arabic for a long time now, or at least the part of the world that has paid attention to what Muhammad and Co. have done to the previously Christian (and Zoroastrian, and Buddhist...) lands that are now Islamic. Just last week I got into a weird discussion with a Coptic friend from church about why Arabic is not in and of itself good or bad (he is a native Arabic speaker, but openly claims to hate the language, because the Muslims brought it and robbed him of his birthright, i.e., Coptic. He is not the first Copt who I have known to speak like that). He wouldn't hear it until I reminded him that he reads the Bible in Arabic every day, and it is still the Bible.
I once had a Syriac Orthodox friend from Canada whose family had migrated there from Iraq shortly after the rise of Saddam. They moved into an area with a lot of Arabs because that's the closest thing they had to a community at that time (the Baathist regime in Iraq had instituted compulsory Arabization of its non-Arab minorities, particularly harsh on the Assyrians and Syriacs since it meant they could no longer give their children names in their own language, nor teach their children their own language on any kind of official level; the same thing happened to Assyrians in Iran after the revolution in that country with regard to Farsi). Some years ago, my friend's brother had a son, and gave him an Arabic name, Tariq. Their mother was furious, as she had wanted him to keep his heritage in mind. She berated him quite openly for the decision, apparently screaming "That's not a Christian (~Syriac) name! And you can't even SAY it properly! Stupid!"
I was kind of shocked to hear that story from my friend, but I can't really say I blame her mother. There is no love lost between the non-Arab linguistic minorities of the Middle East and the Arabs.