In particular, it's a very East Coast thing. While we have the mom-and-pop pizzerias on the West Coast, there aren't styles of pizza named for West Coast cities and we just don't have that pizza rivalry that the other coast has. There's California-style pizza, but that's named for a state rather than a city, and as soon as you leave California it's easier to find almost any other kind of pizza.

I disagree with the claim that they are, as a rule, universally applicable, though I certainly do not disagree that this is highly US-normative. There is a significant subset of comics specifically about US issues, stretching back all the way to the very beginning. I can, upon request, provide examples.