Except there is, because the zero the article is talking about is the mathematical zero, not the natural language one. In your experience of natural language, z

Except there is, because the zero the article is talking about is the mathematical zero, not the natural language one. In your experience of natural language, zero is a quantity. In math, it's very much not: it's a singularity. Sure, as "that number between -1 and 1 on the number line", zero is mostly unremarkable, but math doesn't really care about number lines that much: as a singularity that arises from mathematical operations, its behaviour, and its "so what is it, really?" is a proper brain twister.