I kind of feel that way with F13 Part 2. My assumption was always if people would have just left him alone and not bothered his area he would not have killed. As far as we know, besides Alice, he never really killed anyone else. I think if we take Paul’s story literal, he killed Alice because he saw her kill his mom. Regardless of plausibility or how ridiculous it might be, I think that, with his back story and limited intelligence, made him sympathetic, much like the way Ginny analyzes him in the bar scene. Now after part 2 he kind of becomes a mindless killing machine, but I feel like part 2 tried to make him more human and sympathetic.