The people in the article you linked showed absolutely no intention of returning, and economics were certainly part of the moving process (note the comments about affordability of healthcare etc). Why are they expats and not immigrants?
Let me put it to you another way: you say that 'the white Eastern Europeans who move to Toronto for a better life aren't "expats"', but as a white Western European who moved to Toronto for a better life why am I referred to as one when they aren't? (I don't think I've ever been referred to as an "immigrant".)
We can take the concept of skin colour out of it if you like for the purposes of this dicussion, although I think it's an inextricable component, and ask why natives of different countries receive different labels for doing and being the exact same thing as each other. I appreciate your attempt to create a distinction, but it doesn't exist in definition and it doesn't exist in the middle ground of reality.
You're not getting my point. Expats don't typically have to jump through hoops to get to the country they want to live in, for whatever reason. I had the option of continuing to work in Hong Kong as a salesman, but I chose not to and came back home. Had I decided to stay, I would've been making about the same as I do know, but enjoying certain fringe benefits that expats enjoy. It wouldn't have been out of necessity, nor would I have benefited much in comparison to being here. It would have been a choice because, again for whatever reason, either a better opportunity came about that I wanted to take a chance on, or I just felt like living there.
You're an expat in Canada because there's no reason why you can't get equal pay at a similar company in England. Americans, Western Europeans, or Japanese with MBAs or advanced degrees don't move to a similarly developed country just to drive a taxi. But you have former physicists in Eastern Europe who drive cabs in London, New York, or Toronto. Same with the brown people you mentioned. I was in a cab the other day and the guy driving me was a doctor in India. Said he could make way more for him and his family driving a cab in the US than being a doctor in Hyderabad.
There's a huge difference. I see it, but you don't. You want to make it about race, because that's your shtick. Those Americans in the article didn't move to Mexico because America can't provide the opportunities that Mexico can. They made a choice. Poor people from lesser developed nations who are ambitious and want more (more than what they can get in their home country) are the ones who emigrate out. A UK college graduate who decides to teach English in Botswana because he wants something different, and because he has the luxury to do so, isn't an immigrant. The guy from Botswana who even with an advanced degree, can't feed his family, has a reason to go to the UK and drive a cab. He's the immigrant.
I don't get why you're making a mountain out of a anthill here.