Most expats leave after a few years. They only move in to make a quick buck with tax advantages and then move back/on to another country.

I suppose they're a form of immigrant, but a very specific subgroup. One that often also doesn't intend to integrate with local culture, so their approach is quite different from most legal immigrants. You can't really compare the experiences of war refugees with Americans that come work in another country for five years, even though they're both forms of immigrants.

I don't just consider the Brits and Americans to be expats, I've also met expats from eastern Europe, India, and South East Asia. Maybe the rich expats don't like to be grouped together with them, but I also consider the cheap eastern European labourers that do jobs like working the fields for half a year to be expats.