It really is the broken window fallacy, but in reverse; that working harder could decrease aggregate employment implies that working less hard (or more counter-productively) could increase aggregate employment.

This is even more hare-brained than the suggestion that we should all work less to allow more people to be employed. Increases in productivity (e.g. working harder) can only be harmful in a closed economy with very fixed consumption practices. Pretty much any country or region, however, cannot be said to exist in isolation, nor does it have fixed consumption. When either world interest rates go to 0% or people become miraculously content with everything they have, let me know so I can slack off, but until then I'm gonna keep working.