The Tezumen were happy. When no amount of worshipping caused the Luggage to come back and trample their enemies they poisoned all their priests and tried enlightened atheism instead, which still meant they could kill as many people as they liked but didn't have to get up so early to do it.Pratchett likes to poke fun at religion now and again, and with this quote, he demonstrates that atheists are fair game, too!
It annoys me when an atheist tries to make it seem that all conflict, all death and destruction, ever perpetuated on the Human Race was a direct result of religion--ignoring atheists like Robespierre, Lenin, Stalin, and Mao--or even going so far as to say they merely "borrowed" religious techniques.
As I have looked back on all the world's conflicts, ranging from the esoteric (The War of Jenkin's Ear) to the tragic (two World Wars, the Cold War, two Iraq wars, etc) it became clear to me what causes wars: one group says "You will do X", and the other group says "Over our dead bodies." In other words, it is strictly politics.
Since religion, economics, ears, land, resources, and so many other things, get caught up in politics, all these things--and much, much, more--can be traced to the cause of some war, somewhere.
Thus, the Libertarian ideal of "Do not initiate force against another person", if practiced by everyone, would do far more to establish peace, than any other principle that I could think of.
And this would be the case, despite whatever other wacky things individuals choose to believe!