I've heard numerous arguments of atheism and morality being poles apart, and I wish to address this in a logical essay.

Let us first assume that morality is completely bound to religion. By that, I understand that morality cannot come from anything else than religion, and that morality of anyone non-religious is merely borrowed.

We know that, in this world, there have been, are, and, probably, will be for many years, many conflicting religions. Conflicting in the sense that each of them consider they are right and the others are wrong. In this sense, we also notice that their ideas are conflicting as well: it wasn't Yahweh who created the world, but Allah, you won't get to Heaven, but to Nirvana, you don't have to burn in the name of Vishnu, but in the name of Ahura Mazda, etc. Their history is not necessarily conflicting, but different (considering that the major religions were mostly hundreds of miles apart, at least, this looks quite normal).

It comes, from that, that we should ask a question: why aren't their moral standards radically different? Of course, there are some minor differences, but they're more on how terms sound, rather than how they apply.

Don't believe me? Try this:

- murdering the innocents: all religions forbid it. 10 commandments, the wills of Allah, the pathway of Buddha, etc., every religion forbids the murdering of the innocents

- punishing the guilty: all religions support it. Be it punishment through death, which is present in almost all religions, or through mutilation, or through various different methods that were inacted in that particular society (I doubt you'll find crucifiction with the Aztecs, for example), every religion supported it in one way or the other

- apparent social equality: all religions support it. We are all named warriors of Allah, followers of Buddha Siddharta, Children of Yahweh, ioncarnations of Vishnu, etc.

- hidden social inequality: all religions support it. Not everyone gets to be a Pope, or cardinal, or Imam, or Dalai Lama...

And examples could go on and on.

I therefore ask: how does it come that radically different ideas are supposed to produce basically the same conception? How does it come that, even though it should be obvious to everyone that they all have quite the same moral code, yet people battle on whose code is the most righteous?

There are two possible sollutions: one, in which all religions are basically the same thing in different clothes, and the other, in which the source of morality is entirely different.

The first sollution would practically mean that all religions are, in fact, representation of the same entity. It is far from being possible, unfortunately. It would be possible if all religions would talk about, at least, the same number of gods. It is not the case, though. From a psychological point of view, it is as well very unlikely. And from the perspective of the believers, more than 99% of the human population doesn't agree with that. 

Thus remains the second possibility, that the source of morality has been mistakenly identified as religion. It wouldn't be the first time it happens that two entities are mistakenly identified as cause and effect for one another. Evolution seems to agree that it is the most plausible explanation, social sciences raise this concept of morality as a human social product at the level of law, etc. So to me, this looks like the only good alternative.

If a reason behind morality as a human product isn't obvious to you as it is to me, I strongly suggest that you learn more neurology, psychology, applied mass psychiatry and sociology.