Not an expert but as far as anon knows their belief system requires it. It is about their plan to build the Third Temple that in turn will bring about the return of their God.
https://www.israeltoday.co.il/read/the-third-temple/
Problem is to build it they have to destroy a sacred Mosque built on the site.
https://www.middleeasteye.net/discover/palestine-al-aqsa-islam-one-of-islam-holiest-significiance
Al aqsa mosque is sacred to both Sunni and Shia Muslims and that has brought them together.
Since they don’t believe in Jesus Christ I’m having trouble figuring out who/what their God is exactly.