Composite nations

So-called “composite nations” e.g. Nations where the majority of the population consists of immigrants (US, Australia, New Zealand, Canada), either aren’t nations at all, or are nations “par excellence”. Clarification: residents of these countries don’t belong to the same ethnic groups, races, religions, etc., but, when the Chinese says that he/she is an American, it sounds more convincing than when, for example, a Bosnian says that he/she is German.