The question has a many layered answer. One reason is that more and more people who were not particularly religious to begin with are "coming out" as social pressure to be connected to a religion (especially Christianity) diminishes. Another answer is that some people are just atheists or agnostics--they either don't believe or they question the know-ability of the divine.
Still other reasons have to do with what is happening within certain religions: some people do belief in the divine, but do not see value in organized religion for all sorts of reasons; some people are just fed up with religious organizations and want nothing more to do with them (the so-called "dones"); some people have never given religion much thought and really do not know what they are (the so-called "nones"); some people have been genuinely harmed by some religions and their practices and are refugees from religion--the spiritually abused, and finally some people start off in one religion and change to another, such as a Christian convert to Buddhism and so on. I hope all that made sense. I believe as society becomes more diverse and complex, you will see more of this phenomena as well as one already in the making; cross-pollination among religions and secular views (pandeism represents something of that order) and religion-to-religion cross-pollination such as Zen Christianity and socially engaged Buddhism (borrowing from the Social Gospel of Christianity in helping and advocating for the poor and disenfranchised).
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.