The author is a professor of computer science at Georgetown who has authored numerous books on how to do well in school and career by minimizing distraction and increasing focus. He's arguing against the California 32-hour work week bill, which he says will be counterproductive on its own without addressing the core problems of excessive coordination and multitasking that is what he believes is truly burning out knowledge workers more than sheer volume of hours.
He is calling this "slow productivity" in honor of a movement from Spain dedicated to cooking instead of eating fast food, which takes longer but is ultimately more enjoyable and rewarding.
How on earth this gets interpreted as media damning right wing work ethic is maybe one of the more bizarre things I've seen happen on HackerNews recently.