I didn't find him to be complaining about anything per se, nor mentioning "fulltime job":
Never mind that a good programmer can produce more valuable work in a 30-hour workweek from home than a crappy programmer can toiling 60 hours in the office.
Rather, he's pointing out a contrast between two extreme, but plausible, situations.
This guy is offloading that problem to his manager
What's the manager's job if not, as you put it, to manage the communication and signaling problems that creates in the workplace? Still, I come back to the impression that you're thinking about this out of context:
doesn't seem to understand the problems he might be creating.
Again, I allege that's not the programmer's job. The programmer's job is to create, and the manager's job is to maximize the creativity while minimizing problems.
It's that I don't think his sarcasm offers any practical advice.
I agree that the practical advice may be masked by the tone or form.
This is the advice as I interpret it:
If you want to maximize the productivity of your programmers and ensure the most talented and most producive ones stay, avoid the listed behaviors, even if there are some negative consequences. If your business is software, I have a hard time believing that "general productivity" among the others in the office would improve enough to offset getting rid of someone working on the core competency.
On the other hand, I could easily imagine a situation, however, where this is not the desired outcome, such as in a company where software is only a minor component. In that case, your firmer hand on scheduling seems far more beneficial.