From the look of things, i have come to realise that all atheist are from a christian background for i have not seen any atheist who claimed he once believed in islamic or any other religion asides Christianity. Meanwhile, all arguments by atheist are always against the Christian faith. Who else have observe this and Why is it so?

I have also noticed this trend...
I don't blame them sometimes, because they fall into the hands of false, deceitful Christians..

This is because unlike her half Sister Islam, there is no Death for Apostasy in Christianity..

voltron: This is because unlike her half Sister Islam, there is no Death for Apostasy in Christianity..

^^ datz d truth. Christianity givez u a frêe hand.

There are more closet atheists in the North of Nigeria.
They're too scared to come out.
Of course you know what happens to people that confess to be atheists, even in the South.

Its just for two reason... 1) is the law of probability... You are more likely to find a christian atheist due to the lager population of christianity... 2) no muslim who declare himseld to be an atheist and still have his head standing on his neck... So the muslim atheist will just keep mute about it...

Very good observations,I thought I was alone in these observations. While believing completely with the reasons so far stated,let me add some more reasons why most of the atheist always come from christian backgrounds:
1. Unlike most other religions,christianity is the most under attack by the devil. He knows the religion(permit me to use this) that is a threat to the kingdom of darkness and hence will do everything within his power to draw men away from christ,those atheists whom you see are the ones he has succeded in drawing away. Satan won't waste time on a religion that isn't threatening his kingdom. That's why he(and his agents) will magnify the story of a pastor that commited sin while imams,etc will commit all sorts unnoticed.
2. Christ by his death on the cross bought us liberty from the curse of the law. Most christians abuse this liberty so much that they see it as their freedom to choose. That's why some will choose to become atheists. This is even why more criticisms of men of God come from people from christian backgrounds,but you will never hear a muslim attack an alfa or imam,no matter what he does.Most other religions don't have such liberty as we do in christ.

Like someone mentioned above, there are probably just as many, but nobody wan die ontop this bullsh*t now

If you're looking for a nairaland example though, mazaje used to be a muslim. I'm sure there are a couple others

Even though Islam has a way of using TOTAL FEAR to indoctrinate and enslave its adherents more than christianity, there are some atheist that were former muslims. . .Islam does not recognize atheism, it advocates for the death of atheist, muslims don't see atheist as humans that are worth living, so muslim atheist are very much in the closet. . . .I know about 2 former muslims that are atheist here on nairaland even though they don't post anymore. . . .A recent poll showed that there are actually a lot of atheist in Saudi Arabia more than 10% of the population but you'll never know about them because they are really hiding in the shadows. . .If they come out they will be killed. . .Islam is a dangerous religion. . .

Op, think globally.

Actually, many (if not majority of) atheists come from Buddhist or confuscianist backgrounds if you consider Japan. South Korea and China.