In relationship to the story, Zushio’s father is speaking on how to govern. With this context “Everyone is entitled to their happiness” is an interesting contrast to the suffering Zushio and his family had to endure.
Discussion
There’s a short essay by Mark Le Fanu you might enjoy here:
https://www.criterion.com/current/posts/2678-sansho-the-bailiff-the-lessons-of-sansho