All humans are conscious,
Conscious people can suffer,
therefore it is morally right to keep all people from suffering.
You'll notice that there is a significant logical step missing here: Suffering is absolutely bad. And of course, based on a purely evolutionary/materialistic worldview he is simply unable to make this claim, which is why he leaves the premise out. Nevertheless, it is a good read, easy, short, and it is important because it presents a worldview which Christians are being forced more and more often to confront:
The Mystery of Consciousness