You may be right, but have you driven through that area? Hotter than hell in the summer and miles and miles and miles of produce as far as the eyes can see. Pull up some google maps and see for yourself. It takes a lot of water.
Its a fair question though, not sure if we could even verify it. The amount they use vs what Fiji requires is probably a rounding error I would guess. I wonder if they save it off underground somewhere for later use? Didn't the article say they own some underground water supply?