Because it has become something someone can hold on to whenever they are in deep !@#$%^&*. They keep themselves optimistic with their faith. In that way religion is as important to anyone as a best friend you can hold on to, and it's only natural to defend that because people attacking it would mean you'd lose your hold-on-to thing, again, comparable to a friend. Otherwise, most people that don't understand something are eagerly saying it was God that did it, or made it or whatevered it. Well it might satisfy themselves, please, don't bother anyone else with it, it's annoying as !@#$%^&* (and this creates the anti-religious thing anyway). Btw people that don't care if god exists or not, like me, are not really atheists are they ?