Night seems to think that we're born believing in some religion or other.
We are born without religion. What religion we pick up, if any, is taught to us at some stage.
Even some Christians acknowledge that simple fact and do not count their children to be "Christian" until they are old enough to understand and make a mature decision
whether or not to be "Born Again in Christ"
Whilst most people are born into a family that follows some religion or other or into a society that crams a given religion down the throats of its people, that is by no means universal - especially these days when burning non-believers (or believers that have differences of opinion) has fallen out of fashion in most places.
So that mechanism of being taught to believe a given religion is not, by any stretch of the imagination, universal or "default".
If a person grew up in Utah or the Bible Belt or an Islamic nation that bases its entire law structure on scripture, then the likelihood they've been fed the tenets of a religion along with their mother's milk is very high, but in other areas that likelihood is less.
The idea that a person is "Religious by Default" and has to
have some "reason" to stop believing is pure crap.
It may well be how Night arrived at a state of atheism, but it is certainly not the only way. It may well be a very common way, especially in areas that are highly influenced by religion but, again, it's not the only way.
Hollywood - and Night, it seems - perpetuate the myth that religion is "natural" and that those who are not religious must have had some traumatic event to make them anything other.
In this modern day and age, it's perfectly reasonable to portray a character who has never had any religious indoctrination - for example, a child of two atheists (such as myself) - and therefore not be religious to begin with.
Sure, in most countries, children of atheists would be aware of religion and that there are people who believe in some religion or other (the mainstream religions aren't shy about ramming their beliefs down everyone's throats through the various media or bashing on doors at ungodly times), but that does not equate to the child being "religious" and they have no belief to lose due to some plot-convenient trauma.
And even among those who were raised in religious families, "leaving the faith" is very frequently a matter of gradually coming to a personal realisation that the religion doesn't work for them and a "drifting away", rather than a cataclysmic "my mummy died horribly so therefore there can't really be a god."
No offense intended to any adherents of any faith in my pointing out of the less than stirling behaviour of organised religions.