The root comment never implied that a zero or one day work-week was the inevitable consequence of the four-day work-week, so I don't think it was a slippery slo

The root comment never implied that a zero or one day work-week was the inevitable consequence of the four-day work-week, so I don't think it was a slippery slope argument. Their argument seemed more like a reductio ad absurdum, because they took the basic subject of the article to an extreme, and asked why not.