If you're talking about crossing country borders, then maybe. If you're talking about distance traveled, I would venture to guess that Americans on average travel further distances. The United States of America has states larger than many countries in Europe.
Citizens of the world usually refers to cultural exposure and appreciation for differences around the world. I have never seen it refer to distance travelled, however I can see how some Americans can use that definition to try and change the topic
Are you under the impression that the United States doesn't have a diverse mix of cultures, or that people here don't appreciate differences? That's literally what the "great melting pot" thing is all about.
