Earlier quoted context omitted.
immigrants are people who tend to stay and don’t have plans to return to their home countries. Expats are temporary immigrants typically paid by their company to move and intend to move back to their home countries once the assignment is over.
Ain't nobody calling seasonal minimum-wage workers "expats".
Also an ex-patriate is typically in the professional class. So those "English" teachers who teach in Japan, etc., may think of themselves as ex-pats or try to frequent "ex-pat" hangouts but they aren't necessarily because of two things: one, they have not been working at their home office and then transferred and typically they do not hold prelesional degrees -though they may hold "certificates" or whatever. They are in effect temporary workers on a limited stay visa, often needing annual renewal by hopping to a third country to have it renewed themselves. For ex-pats all this or arranged by their employers.