This seems like an odd error for the article to make. The great pyramid in Giza is nearly 50% taller, was built nearly 2500 years earlier, and still stands today.
Why does it “stretch the limits of what it means to be a building?” As far as I understand, the Giza pyramid was built block by block like any other building. Both building probably didn’t many people going to the office every day in them, although the lighthouse probably had some light keepers enjoying a better view than folks keeping the triangle gods happy.
The aquaducts and viae were built block by block too, but they're, I hope we agree, clearly not buildings. In my mind at least, the pyramids are too close to not having an inside relative to how big the outside is -- like how you wouldn't call a mine or a tunnel a building either.
Words are fuzzy concepts meant to convey ideas. Etymologically, I imagine the pyramids are "buildings" in that they're things that are built, like you're describing, but in my internal idea of what a building is, pyramids are too close to just being a carefully shaped mountain. There's also the issue of the fact that they weren't designed for _any_ living person to stay or visit, pushing it closer to a "monument" or "memorial" or something than a "building" in my mind.
Interestingly, if there were more internal space or if they were actively used by people (at any point in history) instead of just being left to the dead in the sands of time then it'd be a lot less clear-cut for me.
I'm not totally sure how other people use that word, but a (obviously biased) survey of the top 10 people I knew would care and respond quickly unanimously called the pyramids of giza "not buildings," the most common alternative description being a "monument."
Kufu's pyramid was actively used. It's the only likely reason for the design of it's portcullis, which doesn't defend as well against entry as previous designs, and is equipped for repeated opening. Plenty of information on the topic here:
Your reasoning is well taken and haven recently read Hofstadter's "Surfaces and Essences" the idea of what is a thing and what is not is fascinating.
Some of the criteria are questionable to me. For example, some monuments or memorials are still buildings, such as a mausoleum. Would your survey respondents deny a mausoleum is a building?
I could also ask myself, would I consider the Statue of Liberty a building? It is in active use; it has some usable interior volume; it is free-standing above the surface. And yet I hesitate to call it a building more than I hesitate to agree a lighthouse is a building.
Without exploring etymology, what strikes me as interesting here is that buildings are generally structures in which we live or work. Mausoleums and pyramids are interesting in this regard because they are the opposite: they are places for the dead. Perhaps it is this use rather than the actual form that is cause for debate in the description of building, given that a building can take so many forms even in our agreed definition of the term.
It's about what you define as "free standing" i.e. self supporting, which at least means no wire anchors, but arguably also means no pyramids because they are a sort of refined mound, no ziggurats, no cheating by excavating around mountains and putting a cap on it
