I don't see anywhere in the GP post where he mentions the law or the fear of punishment from it.
I hope I'm wrong but your post seems to be implying that limited term copyright is somehow dishonest.
This is exactly the misconception that the GP post was trying to correct. He is saying that authors cannot own words and that as a society we have granted them something they don't naturally deserve- a temporary monopoly on that expression of human thought.
You seem to be implying that putting pen to paper means that authors naturally and for all time own that portion of humanity and that anyone who thinks otherwise is dishonest. This point of view (while promoted heavily by media corporations in recent history) is not historically accurate and would undoubtedly harm the whole of human art more than it would help the enriched author's descendants (or publishers).
Pointing out the temporary nature or history of that very-unnatural monopoly by no means implies dishonest intent.
If I misunderstood your post I sincerely apologize.