What is behind the anti-Israel, anti-Jewish attitudes of many Christians from the Middle East? It is because many are Arab and there is great anti-Semitism in the Arab world. Second: They live in Moslem dominated societies and are bombarded daily with anti-Jewish, anti-Israel propaganda. They soon accept the propaganda and begin purveying it themselves. While their religion is Christian, they, as Arabs and Middle Easterners, are culturally, attitudinally, and in ways of habit similar to Moslems in outlook. Many have family members married to Moslems.
They also retain the original anti-Jewish attitude from the early Eastern Christian years, based on a Replacement Theology justified by claiming the Jews were sinful and therefore replaced by Christians. The re-establishment of the State of Israel was a theological blow for many Mideast Christians who were certain God no longer favored the Jewish people. They remain in denial regarding the existence of a Jewish state. They don’t want it.
Many consider the Jews alien and European, since many Christians are Arab or partially Arab. They will not let themselves feel part of a Jewish state. So, when in the late 1960s the Moslems in the region began identifying themselves as "Palestinians," the Christian Arabs also began identifying as Palestinians as a way to distinguish themselves from Israelis/Jews. (Ironically, up until the 1948 re-creation of Israel, the Jewish residents were called Palestinians, a name originally given to them by the Romans.)
Many feel part of the "Palestinian" rebellion and, like the Moslems, many would like to see the removal of the Jewish State. No doubt, many have been terrorized and threatened by local Islamic groups and have cast their lot with them so as to survive.
Perhaps, the most important point is that they are not Americans. Americans, be they Protestant, Catholic or secular, are a very open, gregarious, and tolerant people. But, in the Arab/Moslem Mideast, much is based on tribalism, clan, ethnic or religious identity. These are not societies built on the openness and free-flow we have here. Americans are exemplary people when it comes to openness. In contrast, many European Catholics still remain anti-Jewish, as are many of the Latinos coming here from south of the border. Perhaps in a generation or so the Middle East Christians who have settled here may become less anti-Jewish.
Finally, there is the envy factor. Many are jealous that Israel has produced a strong, independent country whereas Christians have not done so in the Mideast. Israel chose independence and great sacrifice, whereas the Christian communities allowed themselves to be subsumed under the Islamic majority. They made alliances with Moslem groups. Perhaps, their Christian ideals taught them not to fight, a form of pacifism. Whatever the case, their way to answer that failure seems to be condemning Israel. Israel, in their mind, is somehow foreign to the region and doesn't belong there; the familiar scapegoating routine of Jews being "too successful, too wealthy, too represented." In other words, the Jews are guilty... because they are successful.