Why should he? Just because some randoms on the net think they own the site after hanging there for some time?
This seems like a really communist take, but it seems to me that if a site derives essentially all of its value from UGC and the work of moderators, it would be much more fair, if valuable contributors and mods had a significant ownership stake in the site. Perhaps a site will someday emerge with that model. Obviously, such a site would also need to actually BE at least mildly-profitable of course for that to make sense, which is not a trivial achievement.