"Whether it's China or Japan or Mexico, they are all taking our jobs." -- Donald Trump
Whatever one may think of Donald Trump, one thing he is not is naïve. So does it make sense when someone like Adam Davidson (or Jonathan Portes) claims that worry about immigrants or foreign countries (or robots or non-retiring seniors) "taking our jobs" are based on the "something called the Lump of Labor Fallacy: the erroneous notion that there is only so much work to be done and that no one can get a job without taking one from someone else"?
Of course not. These folks are just mouthing platitudes they've heard without a thought to where the platitudes came from, whether they make sense or whether they are persuasive. (See also Sandwichman's Lump-of-Labor Odyssey)