Why? This is what I observe.
(1) I have read a number of books by the Dalai Lama, and have concluded that he does not believe anything about his religion other than the personal, psychological benefit it
can provide.
(2) There are Christian churches in the U.S. allowing Muslims to use their Christian churches for Islamic worship. That is admirable, I believe, but you can't tell me those people really believe their religious texts. All gods are jealous gods.
(3) When contemporary Americans justify their religious beliefs, they always tout how religion makes them a better person, but they never say it is because they actually believe the words of the Bible. They never say it is because they believe in the holy trinity , heaven and hell, angels, holy sacrament, the resurrection, the story of Job, ...
(4) Everywhere religions are becoming more and more tolerant of other religions, even though it is arguably impossible to do so while staying true to scripture.
For these reasons, religion in modern countries share two trends. First, they distance themselves from much of their holy scriptures, instead believing all religions to be different paths to a similar sacredness. Second, this secularization occurs while reserving a belief in a sacred something that gives people a psychological benefit.
For these reasons, I don't think anyone really understands the role of religion in modern societies (the philosopher Daniel Dennett has made the best attempt thus far), but whatever its role, it promotes a social harmony like it has never done before, such that Humanists must resign themselves to [largely] attacking its historical role and its role in developing countries.