Why not go the whole nine yards and adopt atheism? — Agent Smith
Much of the deep-seated meaning and the resultant seemingly disparate array of meaningful influence that religion has had upon so many different kinds of people throughout the known history of humanity is found lacking in atheism. That's as it should be, given that atheism is a lack of supernatural belief, generally speaking. More specifically speaking, it is often described as a lack of belief that there is some supernatural creator of the universe. The point is that people have attributed a whole lot of meaning to gods and other supernatural entities. To some, religion gives answers to some of life's most important questions. Some of these questions, atheism has no answer for.
It is no accident that so many different people from so many different corners of the earth throughout human history all found themselves with explanatory needs; gaps in their knowledge base. No, that is no accident at all, my friend. To quite the contrary, Gods are just one kind of supernatural explanation, and we invented supernatural explanations out of necessity. Nowadays, many atheists dismiss them due to lack thereof. Supernatural beliefs are part and parcel to the everyday lives of most, I would dare to guess. It was necessary. I mean, in prehistoric days, people took note of the sun. Some got sunburned, and put two and two together. Some noted that certain animals only came out at night, and because they wanted to eat them, those people would wait for the sun to disappear from the visible sky while planning a hunt. Others wanted to know "why" the sun traveled in the sky the way that it did. People wanted to know what it was, this bright object in the sky. All this only to say that the sun - like all meaningful things - became more and more meaningful as people attributed more and more meaning to it. In short, we do this by drawing correlations between the sun and other things. At some point, we gave the star at the center of our solar system a name, and began using that name to pick it out to the exclusion of all else, all as a means to talk about it. Some worshipped the sun, which is not such a far stretch for a bunch of ignorant humans seeking to explain stuff.
So, it seems likely to me at least that the gap in our knowledge base is
the origin of the gods throughout known history, including the God of Abraham.
I find that many raised in some sort of 'Christian' background, have a hard time shaking the vestiges of the religion. Some of those remnants have become codified by American law.
Anyway, to get back to the question asked at the top of this post...
It's takes a certain kind of person in a certain kind of situation in order to have what it takes to lose their religion. I can only tell you my own personal experience:It's not easy. Many find it difficult or impossible to find personal meaningful contentment and/or fulfillment without relying somehow upon some supernatural belief or another. In short, religion is far more meaningful to religious people that you seem to realize.