Hmmmm, if you go to Table 2.07 in MOS Part 91, the 'flight visibility' column (4) is separate from the 'operational requirements' column (6). So if we take my favourite item for present purposes - Item 4 - the 'flight visibility' column says "5 000 m" and the 'operational requirements' column says "Aircraft must be operated in sight of ground or water".
Given the definition of "flight visibility", the "5 000 m" seems to me to mean that the atmospheric conditions in flight (note: "flight" is also defined) must be such that when you look forward from the cockpit you are able to see and identify all "prominent unlit objects by day" and all "prominent lighted objects by night" that are 5,000 metres or closer to you in that direction. If there happen to be no such objects 5,000 metres or closer to you in the forward direction from the cockpit, it does not matter that you cannot see and identify objects that do not exist. But the atmospheric conditions must be such that you could if they did.
I do not think it follows that the separate operational requirement can be interpreted as meaning that the aircraft must be operated in sight of ground or water, unless the ground or water cannot be seen from the cockpit. As I've said before, that would render the operational requirement meaningless.
What we don't know is the level of detail that must be discernible. I don't think it goes as far as "every tree, chicken coop, horse and cow".
And I reiterate, all of this is why the old and not so bold 'weekend warrior' NVFRers I know only do it on moonlit nights.