This post will likely cause a little bit of controversy, despite being very high level and not taking sides in any kind of conflict. If you are close minded or take offense easily, feel free to skip over this post.
I've spent a great many hours thinking about religion, its role in society, and how people interact with it. To be blunt, I'm not a fan. It can lead to great things, but people take a very odd look at it.
I split religion into two parts: the philosophy and the theology. The philosophy is how to live a good and moral life. The theology is the supernatural carrot and stick that makes you follow the philosophy. A religious person would probably say that you can't have one without the other, but Buddhists and atheists have been proving that supposition wrong for a very long time.
Everyone follows a philosophy, but very few examine what that actually is. The vast, vast majority believe that rape is wrong (thankfully), whether or not they are religious. Very few think about why they believe rape is wrong, however. A more divided example comes from several decades ago, during the Civil Rights movement. Looking back, you'll find the religions and non-religious on both sides of that. You see the same thing in today's debate about same-sex marriage.
Not everyone follows a theology. Not everyone needs or wants a supernatural being (sometimes more than one) to enforce their philosophy. Society in general seems to give enough of a carrot and stick to make a theology superfluous. Laws generally follow moral guidelines, as does societal approval. Being liked and respected comes when a person lives a good and moral life.
As most people do not want to take the time to think about their philosophy, or are afraid they wouldn't have one otherwise, they turn to religion with its ready made philosophy. Typically, they grew up being part of a religion, and have no urge to think past it. Each religion, and their various denominations, have their own take on philosophy and theology.
It's late and I need sleep, so I'll finish off with a quick note: if you're curious about the pure philosophy of Christianity, read the Jefferson Bible. I have yet to read it myself (and I do plan to do so), but it's Thomas Jefferson's collection of the sayings of Jesus without the supernatural elements. As someone who does reflect on their philosophy, and someone who does agree with much of the philosophies of Christianity, I look forward to this book very much. Jefferson, while not a Christian himself (he was a Deist), greatly respected Jesus the philosopher. I can think of no greater endorsement.