Why are white people expats when the rest of us are immigrants?

What is an expat? And who is an expat? According to Wikipedia, “an expatriate (often shortened to expat) is a person temporarily or permanently residing in a country other than that of the person’s upbringing. The word comes from the Latin terms ex (‘out of’) and patria (‘country, fatherland’)”.

Defined that way, you should expect that any person going to work outside of his or her country for a period of time would be an expat, regardless of his skin colour or country. But that is not the case in reality; expat is a term reserved exclusively for western white people going to work abroad.