They were being facetious, it's a critique of the racist/classist tendency in our language to label people with brown skin living in another country as "immigrants" but white people as "ex-pats". It's related to the history of WASP colonialism.
I think they tread the line in reverse here: I don't think LA Times would put out news that call for immigrants to "go home" but it's fair game when they call them expats.
They don't like being called immigrants since they use it in a mostly negative context, so they are expats :)