As a Christian of Arab origin, I can corroborate that the anti-Israel view is pervasive among Christians from the Middle East, even those who are professing Evangelicals.
I have spent time—in weekly Bible studies—with with Arabs from many countries, including Syria, Lebanon, Iraq, Jordan, Egypt; Evangelical Protestants as well as “nominal” Christians from Orthodox and Maronite backgrounds. Most of them have adopted the same views of Israel and the West as are held by the majority Muslims in their respective countries. They may not be overtly virulent anti-semites, but if you ask them to support a pro-Israel group or political position they’d most likely give you the brush off.
This would have been what started to set people off. Cruz is going tell a Christian who was saved from ISIS by Assad that Assad is the same as ISIS? That's just trolling. And it just snowballed from there.