I'd think that RP contributions to a community lore belongs to the community in question - especially since anything added on to community lore is founded on, and only makes sense within the context of said lore - and made explicitly and exclusively for the enjoyment of others who follow the lore.
Take any faction, for example. The players dictating the RP of the [LN] or the .:j:. don't own the story of either faction. Have they changed the faction since its vanilla roots? Definitely. Have the leaders injected their own originality and creativity into changing the faction? Certainly. Can the leaders of either faction exercise the right to close down shop and restrict anyone from doing anything with the Liberty Navy or the Junkers? Certainly not.
Sure, the circumstances of vanilla factions like the LN and the Junkers is a little different from the circumstances surrounding factions like the Phantoms, the HF, or the Reavers - but if the concept of 'ownership' in the sense that the authors are granted indefinite exclusivity and authority over what happens to his or her "original content" doesn't extend to everyone that's injected their creative product into lore, then is it really a concept of ownership, or is it just a special case of sentiment?
