In my opinion among that “all wars are caused by religious belief.” But is that actually true? Does religion cause war?
Very seldom. Wars are about control and ownership of physical territory. The winner gets to impose his or her laws, steal what is easy to steal, and to reap the taxes of the populace. Sometimes the conqueror will go further, using their power to require new behaviors of the conquered populace. In the unusual case where the central reason for a war is to impose an idea, and if the idea is a religion, that war may be due to religion.
a confirmed atheist and tyrant, was forced to let the Orthodox Church open up and function a bit during World War II. It simply kept people more willing to die. Religion is a very good way to motivate and console the people who actually have to fight and die in a war.
So, to answer the question: Does religion cause war? Not really. Rather, the all-too-common truth is this: