I don’t think a puritanical work ethic necessarily is unhealthy, but in your example I would consider the guilt aspect to be.
In your example puritanical work ethic + (irrational imo) guilt = you exceed your contractual requirements to deliver work to your employer.
Keep the work ethic but take the guilt out and perhaps instead you’d meet but not exceed your contractual obligations to your employer, and then organise the rest of your time around industriously working on something else that you’re personally passionate about.
The second example could be unhealthy depending on how you approached it, but I wouldn’t say that it necessarily is, and I would say that it’s a big improvement over the first example.
"Puritanical" is definitely meant to imply unhealthy, which is why it's got such a negative connotation. I think even in your example, you substitute "wasted" productivity (in the sense of going beyond contractual obligations) with other productivity, albeit towards another direction. I think that's what the parent's post is pointing out: this obsession/compulsion with filling in all time with productivity. Why can't time just be "wasted"?
In your example puritanical work ethic + (irrational imo) guilt = you exceed your contractual requirements to deliver work to your employer.
Keep the work ethic but take the guilt out and perhaps instead you’d meet but not exceed your contractual obligations to your employer, and then organise the rest of your time around industriously working on something else that you’re personally passionate about.
The second example could be unhealthy depending on how you approached it, but I wouldn’t say that it necessarily is, and I would say that it’s a big improvement over the first example.