The understanding between the reader and the author in this book ends up being something like this: "Isn't it funny that these problems are similar to our modern political problems in the Middle East?" The implication of such an idea is that today's modern problems could be understood in much the same way. If Muslims are regarded as pagans and enemies of God, then there won't be peace in Jerusalem, and if the Muslim world doesn't delegate power responsibly, they won't see peace in Syria or Egypt.
When Saladin is awarded Syria and Egypt as a gift, he is very famous, and the Muslim world universally heralds him as a hero—but that doesn't mean it was a good idea to randomly make him king of two nations. The implicit criticism is that the Muslim world has historically delegated powers in a chaotic way. Saladin is a Kurd, by the way, meaning potential conflict between the Muslims and the Kurds if this arrangement goes south.
In Jerusalem, the battle is about human dignity and respect. Although the Christian nations are supposed to be shaped by Jesus's pacifism and open-mindedness, these Christian Crusaders are basically invaders, using religion as an excuse for violence. Therefore Saladin's victory signifies the sustainability of the Muslim world, and indeed it has survived, which means wonderful things for the diversity of the earth.
