He probably could have done away with the first part, which seems mostly to be intended to introduce the topic of unacknowledged assumptions. Then again, it's entirely possible that I'm reading my own opinions into his words....
I realize that's a fairly common assessment, but the reality is that, like all scientific theories, evolutionary theory is descriptive, not prescriptive. It is entirely silent on the matter of how we should live our lives, or should behave towards others, or should function as a society.
The author himself acknowledges that. The problem comes in when a materialist or objectivist begins to address the question of how we should live our lives, etc. (And we have yet to discuss why such a thing is even necessary.) On what foundation might a materialist build his moral system? How would he identify what was moral or immoral, and on what basis could he conclude that a competing moral system was wrong?
A materialist's choices for constructing a moral system are pretty limited: he can make something up, he can go by what "feels right," or he can go by what he sees in the world. (A theistic approach offers another option: God can tell us what's right and wrong.)
Of these, the latter can be supported by scientific evidence concerning how beings should act and interact. It's easy to see that the natural world apparently works according to the mechanisms of evolution, which leads to conclusions that are inimical to what we would construe to be right and wrong.
And anyone who claims that the theory of evolution, in and of itself, either justifies or proscribes some behavior is committing a category error of the first degree.
There's no error here -- nobody is saying that evolution, in and of itself, justifies or proscribes anything. It's just that we're not addressing the theory in a vacuum. Instead, we're embarked on a search for morality -- sets of rules for how beings ought to interact. In that case the interactions and processes contained within the theory of evolution are quite relevant to the moral question, because we've got to somehow decide whether or not the evolutionary behavior we observe is morally correct. (And, as our PETA friends would tell you, this question is not necessarily limited to interactions between humans, but might include human interaction with other species.)
We are struggling with the problem of deciding how people should live their lives. The first step in that process is to decide upon a set of moral goals, of which the theory of evolution suggests a goodly number, including "the good of the species," and "might makes right." Neither of these are particularly consistent with the idea of individual rights, but both of them are observably important in the natural scheme of things.
There are of course different materialistic approaches such as, for example, an economic argument based on Western successes (though in so doing, we would have to dodge the theistic basis of Western morality and its related economic successes). But that merely gives credence to the idea of moral relativism, since the requirement for evidence would also lead a materialist to acknowledge the viability -- and thus the legitimacy -- of "might makes right."
What materialists cannot do, is arrive at the tidy set of "derived by reason, no initiation of force or fraud" sorts of principles so beloved by objectivists of the Randian or otherwise libertarian stripe.
OK. And to take a step back: how beings and things dointeract, is not a theory in a vaccum but the product of human thinking. It is anthropological, selective, historical, and concerns itself with consensus.
All well and good, and who knows? You may even be right. The problem is, none of that serves the creationist's purpose of invalidating the theory of evolution. Even if trying to put the theory itself into action - and it's not at all clear that that's even a meaningful statement at this point - inevitably leads to gay marriage, infanticide, communism, or whatever one's particular bugaboo happens to be, that does not mean that the theory is therefore false or incorrect.
And that's generally the object of such exercises. "Evolution, if true, would cause X, Y, and Z. Anyone with half-a-brain can see that X, Y, and Z are horrible, horrible things. Therefore, in order to avoid X, Y, and Z, evolution must be false and incorrect." This is usually classed as argument by appeal to the consequences, but it's basically not much more than falsification by fiat - we simply declare it to be non-existent because we don't like it.
It's a shame, though, that this technique isn't generally valid, when you think about it - there are a whole host of things in this world that I don't like, yet that persist in existing anyway, much to my annoyance. ;)
So are the objects "evil?" Probably not, but they act upon us as if they, and not their user, were evil.
Perhaps. But that's purely a matter of perception on the part of the viewer - show a picture of an iron maiden to an innocent child, and you'll engender no such reaction. His parents will likely react as you predict, but that's because they understand what the child does not - the context of what the thing was used for by someone. You may walk through museums of medieval torture devices from time to time, and while your fellow viewers may react with distaste, it's rather rare that any of them will run screaming for the exits - they understand what the devices were used for, but they also understand that they themselves are in no immediate danger from them, because the users of those devices are missing.
Dernavich's question is: Why does Case "B" have moral implications, whereas Case "A" does not?
Because we assign moral implications to one, but not the other. The "moral implications" are essentially meaningless, however, no matter where you think they come from, unless there is someone to put them into practice. What good does it do to say that X is immoral if nobody agrees with you and nobody abides by that?