Whether this belief is innate or is the product of indoctrination I have no idea. Perhaps it's a bit of both.
The funny thing is that this sort of belief is incredibly irrational because it only applies to "other" not to self. I will explain with some anecdotes.
I used to travel the world quite a bit and i was a heavy user of taxi cabs. Knowing my way around and knowing some of the cues that marked a driver seeking to distract me I was frequently aware of when we deviated from shortest routes. Being that I'm a talkative sort and a student of religion I'd often asked or guessed (from hanging icons etc) the religion of the driver. I got it in my head that the only drivers that tried this trick on me were either Christians or Russians (I will explain). Not Muslims, Israeli, Buddhists or anyone else (including atheists). Hindus? I’m still deciding there but they have a decidedly Christian feel to them. After a while I got into a habit of asking drivers before I got into the cab what religion they were. If they told me that they were Christian or I detected a Russian accent I would close the door and look for another cab. Application of this rule of thumb has resulted in me almost never having to get into an argument with drivers seeking to divert from best route. Note that this rule of thumb does not work in places like Vietnam where almost every person will scam you given the chance.
(Side track on Russians - I suspect this was mostly about timing - I'm not sure - but most of the Russians that tried to scam me had escaped from the terrible post-Glasnost era of Russia where millions starved and survival rates above niceties such as morals. Habits formed in such conditions die hard).
Next. In every case where I have been severely stolen from the perpetrator has been a self proclaimed Christian - and this usually in areas with low proportion of practicing Christians. I'm talking about professionals - financial advisers, accountants, businessmen - you name it. It has got to where I have another rule of thumb - if a person ever tells me that they are Christian (without me asking) then I flag it as an indicator that there is a high probability that the person is not to be trusted whatsoever.
Don't ask me to explain it - I have lots of ideas but nothing concrete - these are just rules of thumb that apply in my life and in the places I spend my time. It might be about me - maybe I have a face that Christians and Russians see and interpret "schmuck" - who knows.
My favorite guess is that Christians have a belief system (as opposed to other religions which are primarily action (or ritual) and not belief) and that at some level they understand that this belief system permeates their world such that if they employ the strategy of cheating (a la prisoners dilemma) they will outperform others.
In other words, a world of "believers" is a world ripe for cheaters. Look at the USA for proof of that - a nation of believers being ripped off constantly by self proclaimed Christians.
I believe that the carrot and stick (heaven and hell) does not stop people from behaving badly. I believe that it is how much fat there is in the land (a la Solzhenitsyn) - in a land rich in milk and honey everyone can afford to be nice. The tougher things get the more likely people will choose not so nice paths to survival. Those who first adopt cheating in environments that are deteriorating are most likely to outperform. Those who cling to fading belief systems for safety fall further and further behind until at some stage they too abandon their rules of morality. When this happens you have a world of dog eat dog chaos.
Those religions that are “archaic” and lean towards very harsh application of Law (ie heavy use of the death penalty) find fertile ground in places that have degenerated into chaos. We all want a safe place to live and raise our kids. In a world of lawlessness the sheriff who comes in with the six-gun and Winchester rifle and systematically guns down the bad guys is a world we all recognize though even this archetype has been stolen by the God-less Christians in their attacks on the poor peoples unfortunately living on top of vital resources like oil.
I can understand those who so fear what seems to be coming to our world that instead of following the path that seemed to be forming since the time of Nietzsche – ie towards universal atheism – they are retreating into what they falsely believe is a place of safety: “God”. The more the world showers harshness upon them the more they desperately seek safety in the pictures painted by those who can profit from their fears and the more those who need them for their power profess their Christianity.
At some stage the nakedness of their “God” will be impossible to deny. At that stage people will turn on each other as they move from one extreme to another. When this happens there will be no salvation until civilization has collapsed far enough that the imposition of very harsh law (probably taken from another “book”) is imposed at the point of gun or sword or spear.
ps. Note that must be said - some of the most beautifully spirited people I have ever known are Christians. Simple, quiet, humble and not proselytizing or making a big deal of their belief - just living a life of goodness as defined by their belief.