It's part of Israel's propaganda to make this about religion to invoke irrational "War on Terror" sentiments in people who haven't looked into it that deeply.

In reality, they're dehumanizing and targeting all Palestinian Arabs, including Christians. Hence the shooting up and bombing of churches along with everything else.

Some of them are Kahanists but I don't think religion figures into their motives as a wider group except for scapegoating purposes.