Fine, he played 6 games. 6, 10, 14. It's irrelevant. He clearly was NOT so incapacitated that he needed to retire due to the injury. The fact that he can't continue to play at the level of a 1m a year player is irrelevant.
Souths chose to sign a player with a long history of shoulder issues to a 4 year contract. He has now succumbed to those ongoing, long term issues.
Argue it all you like, facts are facts, and facts are that he played after his operations so, unless he can medically prove that his condition has worsened since the semi finals, then he shouldn't be medically retired.