Chapter 1 of The Christian Delusion is entitled “The Cultures of Christianities” and is written by assistant professor of anthropology David Eller. He starts the chapter by asking why religion survives despite the fact that intellectual arguments for religion fail or are inconclusive. He believes it is because religion is more about worldview and culture than about beliefs and arguments. Atheists have a hard time arguing Christians out of their religion because most Christians are not argued into their religion.
Eller shows that Christianity is both a part of culture and a culture itself. Christianity spreads into every facet of a culture and other cultures spread into Christianity. He goes on to note the diversity within Christianity throughout history. The point of the chapter is to make it “impossible for Christians to remain unaware of their own religion or of the differences between religions. The hope, and the obligation, is that once people recognize the diversity, plasticity, and relativity of religion, they will see little merit in it: that which is no longer taken for granted is often not taken at all” (p. 45).
His chapter notes that some Christian missionaries realize that it is easier to spread Christianity if you can convert a non-Christian culture into a Christian culture, so he obviously knows that there are Christians who are aware of their own religion and know of differences with other religions. Given the fact that these Christians recognize the diversity, plasticity, and relativity of their own religion and yet still fervently proselytize, it is strange that Eller expects this recognition to result in such Christians leaving Christianity behind.
Eller notes that some Christian missionaries believe that other cultures are false but Christian culture is reality (p. 29). This should have made him aware that Christians are interested in the truth. Noticing the differences between cultures can actually suggest to individuals that one culture is better than another culture. As an American, I am guessing that Eller believes American culture, with its freedom of speech, is superior, at least in this respect, to an Islamic culture that forbids freedom of speech. In other words, he may recognize cultural differences between the U.S. and, say, Saudi Arabia but that hardly leads him to reject American culture (at least freedom of speech). Likewise, his chapter is not going to make Christians see no merit in Christianity.
At best he can hope that this chapter will lead Christians to ask: is my religion true? But then it will become a matter of intellectual arguments. Despite his confidence that all intellectual arguments for religion fail or are inconclusive, about 72% of philosophy of religion faculty members describe themselves as theists or leaning towards theism (compared to 19% describing themselves as atheists).