I don't know anything about Nanashi or Riddy, so I can't confirm or dispute your assessment of them.
All types have access to all functions; an ILE's Vulnerable Fi doesn't mean he has no opinions or sentiments about anything, it just means he's not very good at dealing with such things. Function weakness doesn't mean it's absent in the personality, but that it lacks fine-tuned control and awareness. A person has to focus and concentrate harder to use their weaker functions, which is tiring and produces lower-quality results.
Moral obligation, especially in a general sense, is related to Fi+Ne, while social status is more of an Fi+Se matter.
If that's what it sounds like there's been a miscommunication. Logic and evidence are the only relevant factors when determining the truth of a matter; the opinion of others is irrelevant. I was merely pointing out that your implication (that ideas are incorrect because they are common) is not necessarily true. Popular opinion is irrelevant either way.