This is like how on certain internet forums, people talk about American conditions as if everybody is in America. Start a conversation about labor conditions and people throw around W-2 as if it's some standard thing. Or someone will give you a summary of your rights as if you are in America ("at-will states").

I remember in the early days of the internet, when you came across a postcode field, it had to be a US postcode. 90210 was the only one I knew at the time, so that got put in a lot.