They're pretty clearly not using "the city" to refer to city but instead to a certain density threshold, so pointing out that city limits are arbitrary doesn't really help anything.
> Nobody I know would call that street the city. In my mind, "the city" is, minimally, houses that are a few feet apart, small yard in back/front, pretty much nothing on the side. Frequently, it's 2-3 story buildings, with whole floors rented out as an apartment. That's my "least dense" vision of a city. Anything less than that (ie, full yards) falls into my vision of suburb.
They almost never clarify. What they do is produce silly arguments like this one.