I can't help but feel that this can be said for any country anywhere. Compare New Englanders to Southerners in the US. They are totally different, but they are still wayyy more similar than Southerners are to Cantonese.

It's easy to track differences between people around you, in your country, and very hard to track difference between people in other countries. This creates an illusion of "We are very different, and they are all the same".