It works the same way in reverse. When you search for "something" you don't see that "something" on the UK site, the French site, the German site, etc. In fact, the latter two sites aren't even in English, they are in the native language of the country. So it makes "some" sense that a user on the French or German site wouldn't want to see US listings because, well, they don't speak English.
However, to charge an extra fee to have our items show up on other English speaking sites by default, is petty. It's just more nickel and dimes.