Most Arab Christians in Israel and elsewhere are between a rock and a hard place. They relate physically and culturally to their Arab kin and relate with their prejudices and the nonstop propaganda. But the underling reason is that most of the Arab Christians are Catholic and their Christian traditions are built around Supercessionism or Replacement theology in which Israel isn’t seen as being a part of God’s plan any longer except in a spiritual sense as applied to Christians. In this climate an Arab Muslim can become a Christian and still retain his or her hatred of Israel and all things Jewish. I’m not saying this hatred is hard and fast but it is prevalent and theologically backed up historically and in current thinking. I know because I’ve spent time in Israel with both Jewish and Christian Arabs there.
It is obvious that such anti-Semitism exists among Arab Christians. I have met some. They like to believe that they would not be the targets of Muslim hatred if the Jews were not stirring things up. Their open hatred of Jews is offensive.
As far as I am concerned, such quislings are on their own in their battle against Islam. I will stand with Israel, if these erstwhile Christians don’t want to stand with those who stand with Israel, so be it.