I thought it was just about money.
Respect could be shown through the production of fan fiction, that isn't compatible with IP.
It isn't their rights. They are dead. It's a very simple concept. The rights belong to whoever gets the property. Also intellectual property rights isn't about respecting artists. It's about protecting corporate rights since most intellectual property is owned by mega-corporations and not the artists who created them.
> but we don't respect the artist's desires about what to do with that property.
Who is 'we'? The only person who has a say in the matter is whoever gets the property after the artist's death.
> but none of it is a natural law: it's a set of somewhat arbitrary legal decisions that we made as a society.
I know. That's my point. But regardless, it doesn't change the fact that the artist is dead and has no rights.
Should the sons have respected marquez's wish? Maybe. But then again, the sons probably knew their father better than you did. And marquez must have left the works to his sons for a reason.
As far as I understood it, he was still working on it. And he did not wanted the sketch to be published.
"But then again, the sons probably knew their father better than you did."
Probably. But I would not rule out the possibility, that they have selfish reasons like fame and money.
I think that really depends on what theory of copyright you have operating in your society, many European societies have a theory of copyright that is about respecting artist's moral rights to own what they have created.
If that was the case, nobody in europe would be reading much of franz kafka's works nor anne frank's diary.
But good try!