So it's not gathering when we pick berries because the plant prepared them for spreading its seeds, not for us to eat and end up in our trash. Or we take the tree where the bird nested in, or the beetle, or the abe? Or when we take whatever else we take that something else prepared for another use?

It doesn't fit nicely in our societal view of "yours" and "mine", but whenever you take something, whatever it is, you are almost always taking it away from something else. Surely "thieving" is gathering. It's just a kind of gathering that society has decided is not okay, except in all the cases where society says it's okay, like taking the animals home, or the native humans, and so on.