"they never work nearly so long or hard as any janitor you encounter"
I remember thinking when I was cleaning up construction sites that cleaning the inside of a finished office building must be a job you needed connections or experience to get.
What is tolerable or enjoyable work depends on what you are accustomed to and other factors. Would you rather clean toilets, deal with an irate customer, be on a rooftop in the summer sun, be on an open platform ten stories in the air, or wade in some unknown sludge? Some people have issues with a different subset of those than others, so there isn't a strict ordering.
My point was that it's odd to me to hold being a janitor up as some kind of extreme end of a spectrum. It's not what you do when all else fails. It's not the thing that people with no skills and no experience are automatically assigned to.
However, if a day labor place sends someone to sweep up a warehouse, I wouldn't call that being a janitor. Maybe some would.
I remember thinking when I was cleaning up construction sites that cleaning the inside of a finished office building must be a job you needed connections or experience to get.