I agree, I think it is about revenge, and revenge at that for "a fine disservice," "no simple burn," the mother of all betrayals. To put a more fine point on it, though, I think it's about the process of revenge rather than any particular reason. It's about feeding and stoking that hatred - watering a poison tree. "Screw" calls on both meanings of the word, I think: returning the screw is an image of retribution, also with a nod toward the abstract screw, as in "screwed over."
I agree, I think it is about revenge, and revenge at that for "a fine disservice," "no simple burn," the mother of all betrayals. To put a more fine point on it, though, I think it's about the process of revenge rather than any particular reason. It's about feeding and stoking that hatred - watering a poison tree. "Screw" calls on both meanings of the word, I think: returning the screw is an image of retribution, also with a nod toward the abstract screw, as in "screwed over."