Using the Flat Earth example again, the FES's notions are generally unclear in terms of whether they are actually sincere (still), or that they might be speaking metaphorically, or IMHO from the POV of human experience. Thus it can rather ridiculous to talk in terms of science, without explaining what their actual point is, which might be something like: 'Thinking about the Earth as round is only a conceptual construct which also requires thinking along notions of complex relativity-- in real life, we intrinsically think of the world as Euclidian, and therefore, "flat." The FES might just be claiming that the religious view that all souls be on the same plane, or else that in personal terms, thinking in global terms is just a waste of precious time.
That is very interesting and you may be right that they are arguing from a metaphysical perspective. Maybe you would even start to believe so after reading the Flat Earth Society's website? But, IMHO, a great loss is that you cannot state that in Wikipedia. While Wikipedia allows you to use facts drawn from sources, it does not allow you to interpret sources. You can write that the FES states that the earth is flat, but you can not say that they are using a metaphysical perspective.
Same thing with Daniel P.B. Smith's example:
"The earth is approximately an oblate spheroid (a sphere flattened at the poles.... For many navigational purposes the earth is assumed to be a sphere, without intolerable error."
That you can write that the U.S. Naval Oceanographic Office say. But you cannot write that the U.S. Naval Oceanographic Office says that the earth is round because that would require you to interpret the source. Because of these things, many editors resort to using no sources at all, because a statement without a source is often percieved as less controversial than the same statement drawn from interpreting a source.