1. I think the song is about the colonial time, when England claimed different countries and wanted to oppress them. While the Englishmen lived there they showed strange habits and dindn`t want to conform. In this song the author shows the Englishmen in an ironic and nice way.
2. Such nonsense songs are great to amuse people because they aren't taken so serious. One can deal with a sensitive topic without hurting somebody. Some persons don't think about the song and maybe don't understand it but find it funny and laugh about it. Certain themes can be presented ironically and in a way that only insiders can get the real meaning. So I think some nonsense songs are only nonsense at the first look.
