he ends the movie riding off into the sunset with the sympathetic main character. It is very clear that the film sees his moral stature as having improved over the course of the film. It is in fact the most significant change in character that any character in the film undergoes.
That's not what sympathetic means. It doesn't mean you approve of her the whole time, it means the film encourages you to see her side of things and embrace her perspective. That's true of her the whole time and becomes true of him over the course of the film.