Ok maybe I haven't been paying close enough attention to this show, but I really thought they were going to go a different route with Lizzie. I didn't think her zombie sympathy was well established at all.
I agree that Carol has been the most practical about the situation and her giving the kids zombie survival training made total sense. I thought Lizzie was going to be her most eager (and therefore most troubling) pupil. When she almost smothers Judith, I was thinking "yes. Lizzie. Kill the baby before the baby gets you killed. That's what Carol taught you. Gotta do what you gotta do to survive." So I was expecting more of a "crazy over-the-top survivalist" Lizzie than a "crazy zombie lover Lizzie." I mean seriously. Have you seen those things? They're disgusting. No 10-year-old girl would sympathize with them.
I would have preferred if Lizzie killed her sister because she was judged as a liability, then Carol having to put Lizzie down because she created a psychopathic monster who took her lessons to the extreme.
As much as this episode was an improvement. They've wrapped up the two plot lines I cared about and I'm not sure how they'll keep my interest for the rest of the season. More Carl hijinks and outdated hairstyles? Mehhh.