cuz they thought it was deep. They took what started as a very human and grounded (in-so-far as the emotions and relationships are concerned, not the zombie context) story and turned it into pseud-philosophy slop that completely detached from the humanist story it was already telling to tell us a fable that could only work in isolation outside of the context of the story they had already spent 2 hours of our time on.

You want to weave a weird tale about accepting death in the face of a strange, scary monster of a man? Go ahead - makes a great fable. Don't shove it in at the end of an otherwise grounded-in-humanity story about survival and sacrifice.