The book you suggest RD write would just be TSG again. Anyway, on with debunking this mess:

I wish it had been made clear the house is a bungalow.

when Christians claim that “the atheistic worldview cannot support the existence of moral truth” (discussing the foundation), sometimes atheists hear this as an attack on the roof (“you are saying we are immoral”).

“Oh, you can coincidentally happen to behave well; you just can’t cogently explain why what you are doing is good! Leave assessment of your, or others’, behaviour to the experts, like the Christians.” Oh, that’s any less offensive than “attacking the roof”.

One of the most interesting kinds of “moral houses” is when the foundation doesn’t offer any support for the first floor and roof. When this is not a metaphor, but real life, well, as you can imagine, houses without solid foundations literally fall apart.

I always find meta-ethics tawdry because any answer other than moral realism makes the rest of ethics a waste of time, yet we need it to not be a waste of time; humans just can’t take an “I’m OK with literally anything” stance. The funny thing is no-one ever needs to explain why they think the arguments of meta-ethical non-cognitivists are invalid to get on with the busy work of deciding what to do with sex offenders. This foundation is more of a distraction than anything else.

For the moment, lets [sic] give Dawkins the benefit of the doubt [re: the roof & floor] … However, what kind of meta-ethical foundation has Dawkins provided for his ‘moral home’? Here are some particularly clear quotes on the nature of his meta-ethical beliefs:

Actually, none of the quotations which follow are meta-ethical statements, as I’ll clarify by reminding us of their original in-context meaning. Note also that every single one of these quotations is from a discussion of evolutionary biology, not of atheism, which means that, even if they were read correctly by this theist (which they aren’t), they would not identify the implications of New Atheism, but of evolutionary biology – which, of course, is factually undeniable given modern evidence, so chew on it. Oh, one last point before I dive in: you can’t argue against something by appealing to its consequences being uncomfortable (this is a fallacy called the appeal to consequences), but only to their being self-contradictory (a method I myself use against this theist later).

The universe we observe has precisely the properties we should expect if there is, at bottom, no design, no purpose, no evil, no good, nothing but blind, pitiless indifference.

The universe having no ethical properties is very different from all individual things inside the universe having no ethical properties. Theists don’t know this, however, because pretending otherwise is crucial in the cosmological argument. In the original context, RD discussed the fact that natural phenomena end up happening independently of whether they’re fair, because the universe isn’t conscious.

We cannot admit that things might be neither good nor evil, neither cruel nor kind, but simply callous – indifferent to all suffering, lacking all purpose.

I’ve no indication Dawkins meant to imply all things are this morally neutral; again, from the original context re: evolutionary biology, natural disasters etc., I think the crucial point is that RD objects to the willingness with which humans ascribe intentionalistic (especially divine intentionalistic) explanations to almost all natural phenomena. Indeed, he makes explicit this objection in many works, including TGD.

it is pretty hard to defend absolutist morals on grounds other than religious ones.

Absolutism doesn’t necessarily mean merely that there are moral facts; it can be a stronger claim that moral properties are neither contingent on empirical facts about the world, such as victims’ vulnerabilities, nor admitting of any exceptions. Whenever I discuss the question of whether morals are objective, I find several meanings of “objectivity” being conflated; to me, absolutism mustn’t be confused with things being factual.

We are machines for propagating DNA, and the propagation of DNA is a self sustaining process. It is every living objects’ [sic] sole reason for living. DNA neither cares nor knows. DNA just is. And we dance to its music.

I don’t know whether “objects’” instead of “object’s” is an error in the original or an error in this Christian’s quotation, although the absence of [sic] in the latter source suggests the error is of the latter origin. In any case, this goes back to the naturalism issue above; our cause is DNA propagation, but that’s not to say that it is our purpose or our duty. (Indeed, if it were, that would mean we had one, which would contradict moral non-realism, so this critic who accuses RD of moral non-realism can’t even keep a straight story.) Indeed, DNA propagation is a very interesting type of cause, for which a word like “purpose” is a decent metaphor: it is a context in which an event can be caused by what effects it would have if it happened.

If Dawkins is correct on these matters, then Dawkins is denying that the house has a foundation.

No he’s not, as I’ve explained above.

Without a foundation, the main floor and the roof collapse into the resulting hole.

As I explained above, that’s not true in practice either.

All human behavior would exist in an amoral vacuum.

As I mentioned above, this is a story the theist can’t keep straight anyway because of the word “purpose”.

his point is that morality is a mirage. Morality is a comforting illusion. But these delusions of our brains, while they may promote genetic propagation and the survival of the species, do not reflect anything real about our world.

How can we conclude anything about RD’s views on morality from quotations in which he never even mentioned it? The closest his language came to words like “moral” was in terms like “good” or “evil”, which, as I’ve already said, referred in-context to whether natural but unconscious phenomena exhibit such properties.

it is a valuable intellectual exercise to take Dawkins’ meta-ethical position quite seriously and ask some follow-up questions.

I’ve got a better idea. Go through meta-ethical positions by name, not by owner. Work out which is the most plausible. Work out how important it is that we obtain consensus on that (what should be done with dissenters)? Then see if you can come up with a better method than the terrible one used so far for diagnosing individuals’ opinions on this issue.

If morality is merely a matter of personal preference, is it possible to legitimately judge someone as evil or wicked, as good or virtuous?

What does “legitimately” mean? If morality isn’t factual, judgement isn’t unethical, because nothing is. Of course, it wouldn’t be unethical for you to say judgement is unethical either, because nothing is. But it would be factually inaccurate to say it!

what are the implications for our justice system?

Deterrence, protection of society from dangerous people, changing such people so they are no longer dangerous; these are all non-judgemental bases on which penal et al polices could be defended as politically pragmatic.

how does this change your thinking about actions like a man forcing a woman to have sex with him, one person killing another person for the fun of it, or the systematic extermination of a particular class of people?

Which are respectively things the Bible can let you get away with, things God effectively did frequently in the Bible, and things God definitely did frequently in the Bible. Now who’s got a foundation that doesn’t defend their main floor?