Does this mean if I do not activate a construction building that I need to flip it upside down, like I would do with fields or livestock?Yes, that is correct.
That seems to be how I interpret the rules, but it doesn't work with how I typically explain the theme. I always talk about how if you do not feed your animals or you do not water your crops, then they die and that land just becomes open land. And ducks and chickens and goats are really good at fending for themselves, which is why they do not need upkeep. You can always say that some buildings require constant maintenance and if you don't pay for what needs to be done, they stop becoming useful and gradually they get abandoned.