Excellent thread, OP. You have studied well and I can think of a movie that exemplifies what you are saying here in theatrical form. It is called "Lawless" starring Shia Leboeuf, and it is perhaps one of the finest movies to personify the true difference between vengeance and justice, retribution and redemption. I strongly recommend it for you and everyone else in this thread. Just be cautioned, it does get gory at times and there is some nudity, but the movie as a whole is excellent.