Going back to Langford to start another war against the Emperor would only bring an end to the bliss he was enjoying right now, and while it might be the right thing to do, it might come at the cost of their safety and happiness.
These thoughts he was having were selfish, but he felt like after all Maria had gone through, the universe at least owed her one. She had chosen to sacrifice a lot in her life to get to this point, and there was no turning back for her. He loved her with everything in him and wished only the best for her, but the world didn't, and that was what troubled him.
Zaraki took note of the way Maria waved at Jin, and he wished she could act like that more often. She seemed like a happy child who was excited about life. For some reason, it felt like Jin was the only one who knew how to bring out the child in her, something that seemed lost from the moment she took responsibility as leader of her father's people.