How is this different to any other migrant who misses something from their homeland? Why does it bother you, and why do you see it as an indication of a deficiency of mindset? Shall I similarly hold something against migrants in the UK who prefer something about their homeland? I can't imagine keeping this attitude.
I've lived in other countries but have never called myself an expat. In my experience, the term has been used exclusively by others, mostly non-white people, to describe me.
It's no different from Chinese migrant communities in my hometown calling themselves "Overseas Chinese".