Yes, religious zealots should be parents. We cannot enforce laws saying that some people can be parents and others can not be. Who are we to say that some people deserve to be parents and have a child while others can not? Everyone should be able to have as many children as they want.
Having grown up 10 miles from the nearest small town that to this day does not have a single stop light and under the thumb of a strict religious mother, I still found my way to survive and get off the farm, out of the country. It took work on my part but I knew from an early age I wouldn't be staying in that environment. By working at excelling in school I earned my way to a four year degree that later paid off with opportunities with Fortune 500 companies. My sister wasn't that lucky. She still lives there on that farm. Has 12 children. Follows those same teachings and enforces them on her children. It's another way to die, just slowly and without major life experiences.
Religious zeolite have just as much right to exist and to have children as everyone else. While she should not have murdered her daughter, at least in the eyes of the law, that doesn't mean she should not have a daughter. If she really thought he daughter was possessed she could have had an exorcism.
A poor girl is now dead because her mother believed the daughter was possessed. Religious zealots should not be parents. No parent should ever harm her child in the name of religion. It does not matter what is wrong with the child: The parent should get professional help to resolve the issue with the child.