Once, religion had an important place in society: It served a few important roles, primarily teaching moral values and creating tight-knit communities.

Modernity changed the equation a bit - you no longer need the Bible or the Quoran to tell you how to behave since those all-important values have become an inherent part of our culture today.

The primary reason people reject religion is science - or, in other words, if you embrace a scientific outlook and approach to life then religion usually doesn't make any sense.

But, "Religion" can have many definitions, and does not have to include a "god". For example, I believe Bitcoin is a type of religion (some call it Satoshism, or other such names) for the modern age. If you look at various local Bitcoin communities, you can see all the hallmarks of a cult.

There's also dataism (https://en.wikipedia.org/wiki/Dataism) but I will let you explore that yourself.

In this context, religion can be something even atheists can subscribe to.