There's little consideration for the times where this isn't some sort of voluntary choice. "If you’re not feeling well enough to work, don’t." is fine and well if you've got unlimited sick days, never get sick, or don't have any sort of disability.
I have a cold right now. I would prefer to be off work recovering today but I work on a contract basis; if I take time off work I don’t get paid.
The author is in Germany, so the situation in other places may be surprising to them.
My angle was more about the ambiguity of the status/using the phrase, but I can see how it may appear insensitive to others. It definitely wasn't my intention.