Except it is the specific idea that compels them to resist their occupiers. Because they say it is. Saying otherwise is doing literally exactly the same thing that white Americans did that caused indigenous native Americans to have to change their practices, which they did not see as religious, to fit into the western white European understandings of the word 'religion' in order to receive government funding. Even if a Marxist or materialist analysis of the situation says in general that oppressed peoples 'usually' or 'always' react a specific way because of a specific force, you're missing the point that that is a scientific theory. It is an abstraction. That does not mean it is reality or the only way of viewing a situation.

Your understanding of the situation and how it fits in with your worldview is different than the point of view of the Palestinians actually experiencing the situation. Again, I want to point you to the broad literature of the study of religion that shows just exactly what happens when dudes with white, western ideas of how the world works try to impose those on native indigenous populations.

Your point of view of how the situation works, or your understanding of the powers at play, is not reality. That is your interpretation of reality, a very useful abstraction that is very usually right. But that abstraction has contexts where it is appropriate to apply it, and contexts where it is inappropriate to apply it. And trying to apply it to deny the very real primary motivation that Palestinian people say is motivating them is not a great place to apply that abstraction.