1a=1) Feral individuals (note you continue to cite only feral children) might very well have trouble translating our concepts into their mental language. This is especially the case if they have no intermediate language for communication to others. However none of the conditions wikipedia listed seems to indicate lack of the ability to reason or investigate questions like.
I mention feral children because a crucial developmental process must take place in the early years for a child to become a competent member of society. I don't know what you mean by "feral adult." If you mean someone who grew up in society and later became a hermit, then yes, that person could make moral decisions, so long as socialization occurred. If you are talking about someone who was deprived of human society at a young age and continued to live apart from society all the way into adulthood, then no, such a person would not be likely to be engaging in moral reasoning. The person may be as morally competent as a dog — capable of affection and loyalty and perhaps able to comply with simple rules. Or he/she might be quasi-autistic from the social deprivation, as some cases were.
1b=2) Free Will does not make the claim that your ability to choose would free you from all consequences of the environment. It only claims that there were at least 2 possible options that could have happen depending on your free choice.
Let's say that you grow up in a society that is isolated from the rest of the world. In your society, the common belief is that redheaded people are the spawn of demons and must be killed to prevent the destruction of the world. Redheaded people are hunted and killed all the time. Your parents tell you bedtime stories about heroes who kill redheads. Your childhood games involve smashing objects that are made to resemble redheads. Your coming-of-age involves killing 20 redheaded infants and making their skulls into a totem pole. What will you do to the next redhead you meet? Will you kill him or her, or not? At least two options possible.
Compare your situation to the situation of Bob Smith, who grows up in a different society, in which redheads are treated like everyone else and hair color believed to be a trivial feature. Bob Smith also has at least two options upon meeting a redhead: kill or not kill. According to your definition, both you and Bob Smith have free will and are morally responsible for the decisions regarding redheads. However, you would be likely to kill the redhead and would have to oppose your society's norms not to do so. For Bob Smith, not killing the redhead is the norm. The same action is possible for both you and Bob Smith, but one of you would be swimming upstream. It is certainly possible that you can reject the teachings of your society and refuse to kill redheads, and perhaps even help them. After all, every society has its deviants. But the person you are and the person Bob Smith is are shaped, in part, by the socialization received. There are other shaping factors (e.g., biological tendencies), which may oppose or reinforce socialization.
2a=3) My claim: People who believe Normative claim X form communities. My examples (look at the rational individuals): Politics, Religion [this could be expanded to people with the same beliefs form communities]
Yes, people can and do form voluntary communities, especially in this modern age. However, our formative experiences must happen in social settings we did not choose. There is no way around it. And although people can leave a community they didn't choose, they often don't leave, even when it imposes significant disadvantages (e.g., a stigmatized religion).
2b=4)I assume that you are implying that by living in a society that rejects cannibalism I would find it morally wrong? Sorry, but I was and do not. However I may be an exception to your rule because my parents raised me to try to derive right and wrong from reality not from prior opinions.
You left out an assumption, which was living in an isolated society. When you live in a society that is aware of other societies' practices, it weakens the hold from almost insurmountable to very strong. (The isolation is put in to magnify the effect in my thought experiment.) And yes, you are a product of socialization, though I suspect you overstate your rationality and underestimate other factors.
5) The underlined section contains a Normative claim (in bold). You are claiming that functionality is good. That is a normative claim. If you meant to be applying an Evolutionary perspective you need to refrain from using value judgement because Evolution is Descriptive not Normative. More likely to persist is not better just because it is more likely to persist it is only better at persisting.
However the theory of evolution works more accurately when you follow the gene not the host. The evolution of the Normative belief memes causes the evolution of the societal Norms not vice versa.
Are we not both engaged in description? When you say people have free will and can make rational choices, you are describing them. I think that my description is a better fit for the world as we know it.
What I do is start from norms as observed in human societies and look for causes. The result is that I think that these norms can be parsimoniously understood as enhancing group functioning, though different norms vary as to how well they do this. Norms that enhance group functioning are more likely to persist than norms that impair group functioning.
Is it possible to prefer a norm that undermines the conditions for its continuation? Certainly. But then it will contribute to its own demise, and perhaps the demise of the group. Can you give me an example of a norm that (1) you prescribe and (2) is, on balance, detrimental to any group that practices it?
If a meme is a smaller unit than a norm, then I have no objection to that part of your statement. A particular norm might not work, but some, if not all, of its underlying memes might be accommodated in a different norm that works better. I focus on norms because that's where the rubber meets the road, but breaking down norms into constituent memes may help the analysis.