Christians mostly. Their book says the world can't end unless the Jews control the holy land. They can't enter heaven until the rapture, which happens at the end. No one wants to chill in the dirt for a millenia or two until they go to the good place so they do everything they can to hasten the end days and get to heaven sooner. But they're doing it for everyone, so it's totally not selfish. This is also why they can't leave uncontacted tribes alone, the rapture can't happen until every living soul has been offered salvation through christ, whether they accept it or not. Everyone knowing about Jesus divinity and jews in israel are two of the checklist items to end the game and be judged. So that's pretty much it, Christians support Israel because they literally want to end the world.