In Chapter 10 of The Rage Against God, Peter Hitchens nails down the loosest board on the side of atheism's house. So to speak. Unfortunately for atheism, this does not repair the house, but rather causes the whole thing to fall down.
According to Peter, the atheists "have a fundamental inability to concede that to be effectively absolute, a moral code needs to be beyond human power to alter" (p. 141). That is it in a nutshell. The current consensus is not the same thing as a moral code, and willingness to abide by the current consensus in order to stay out of jail is not the same thing as submitting to a moral code.
Christopher Hitchens wants to say that our morality is innate, and he thinks that this gives him a non-relativistic basis for morality. But the problem is that our internal workings evolved right along with the rest of us. What happens when our innate instincts evolve into something else entirely? Don't we have to go with the flow?
Peter is not distracted in this chapter by Christian failures and inconsistencies. This is just what we would anticipate if what the Bible says about humanity is true. Christians sin because they are people, not because they are Christians. God is in the process of saving screwed up people. It is no objection to this gospel-scheme to point out that the people He is saving are screwed up people. Exactly so.
"Christianity is without doubt difficult and taxing, and all of us fail to emulate the perfection of Christ himself. But we are far better for trying than for not trying, and we know that there is forgiveness available for honest failure" (p. 144).
Or, as the apostle John put it, if we say we have no sin, we deceive ourselves.
And of course, to my great delight, Peter brought up the philosopher Heidegger, not in order to laud some incomprehensible pomo-thingy, but in order to point out that he was a Nazi, and had said that "the Fuhrer, and he alone, is the present and future law of Germany" (p. 148). So much for Heidegger.
Returning to the point that morality is non-existent if it is within our capacity to alter or adapt, Peter says this about the atheist pretence to not be able to grasp this point.
"I should have thought that those who are serious about their unbelief would be relieved by this logic and glad to concede it. If they know, or are reasonably certain, that there is no ultimate authority and no judgment issuing from some unalterable law, they are instantly and quite extraordinarily free" (p. 148).
So why are they so reluctant to grant this "astonishingly simple point" (p. 148)?
"Might it be because they fear that, by admitting their delight at the non-existence of good and evil, they are revealing something of their motives for their belief" (p. 149).
One last comment. This is not an illegitimate ad hominem, or a form of what C.S. Lewis called Bulverism -- showing the reasons why someone might have come to hold to a position, instead of refuting the position itself. What Peter points to here would be appropriate, for example, if a bunch of death row inmates were debating the existence of executioners. Those stoutly maintaining the negative might need to have their possible reasons for doing so pointed out to them. That would not be an unreasonable intrusion.