Why do some movies refer to their continent as “the whole world”?!?

USA is not a continent

When I’ve watched Sliders in 90s I was always thinking – how on earth all significant world scale events always happen in fuckin San Francisco and protagonists being regular men are always involved in them.

I assume its because they have to start taking over the world bit by bit. They just start with the city/country they live in and try to expand. They just get stopped before it happens.

World champions.