There are many legal reasons without moral force behind them beyond "we need to agree on one way or the other" - such as which side of the road to drive on.
We made a decision years ago around copyright (we've modified it since but the general concept is "promote the arts by letting artists have reproduction rights for a time"). We could change that in various ways, if we wanted to, even removing copyright entirely for "machine-readable computer code" and leave protections to trade secrets. Even if you argue "no copyright at all is immoral" or "infinite copyright is immoral" it's hard to argue that "exactly author's life + 50 years is the only moral option".
Switching the rules on people during the game is what annoys/angers people, and is basically what these AIs have done (because they've introduced a new player at low effort).