There are a lot of different positions people could take and I think you often demand unreasonable dichotomies. First, there is something more like a trichotomy of realism, (anti-realist) cognitivism and anti-cognitivism. Only partially dependent on that is the question of extrapolation. One could believe that there is a (human-)right answer to human moral questions here-and-now, without believing that weirder questions have right answers or that the answer to simple questions would be invariant under extrapolation.

Just because philosophers are wasting the term realism, doesn't mean that it's a good idea to redefine it. You are the one guilty of believing that everyone will converge on a meaning for the word.

I happen to agree with the clause you quote because I think the divergence of a single person is so great as to swamp 6 billion people. I imagine that if one could contain that divergence, one would hardly worry about the problem of different people.