(As a longtime fan I'm a bit biased, but I think it's worth a listen to understand the tone: https://www.youtube.com/watch?v=O4SzvsMFaek . The rest of the album also adds some context, as others have noted.)
When you don't have a stable career, or work for long hours for low pay with family to take care of, you wish you had this life. The message can also be taken in a bad way by young people, who then neglect to develop useful skills early on, and ultimately struggle hard to find work. There is so much messaging against good choices in life, that people overlook why they are good choices anyways. I'd rather be at least middle class with the money and freedom to change my circumstances, than struggling with little freedom due to lack of resources.
I don't deny that this is a work of art, and one crafted well, but I just disagree with the sentiment.
https://www.reddit.com/r/radiohead/comments/mhpv3/we_need_to...
(You can hear this clearly if you isolate stereo differences with Audacity: Effect -> Vocal Reduction and Isolation -> Remove Center. Strength 100%.)
"Fitter Happier"
Fitter, happier, more productive Comfortable (Not drinking too much) Regular exercise at the gym (Three days a week) Getting on better with your associate employee contemporaries At ease Eating well (No more microwave dinners and saturated fats) A patient, better driver A safer car (Baby smiling in back seat) Sleeping well (No bad dreams) No paranoia Careful to all animals (Never washing spiders down the plughole) Keep in contact with old friends (Enjoy a drink now and then) Will frequently check credit at (Moral) bank (hole in wall) Favours for favours Fond but not in love Charity standing orders On Sundays ring road supermarket (No killing moths or putting boiling water on the ants) Car wash (Also on Sundays) No longer afraid of the dark Or midday shadows Nothing so ridiculously teenage and desperate Nothing so childish At a better pace Slower and more calculated No chance of escape Now self-employed Concerned (But powerless) An empowered and informed member of society (Pragmatism not idealism) Will not cry in public Less chance of illness Tires that grip in the wet (Shot of baby strapped in back seat) A good memory Still cries at a good film Still kisses with saliva No longer empty and frantic Like a cat Tied to a stick That's driven into Frozen winter shit (The ability to laugh at weakness) Calm Fitter, healthier and more productive A pig In a cage On antibiotics