Why is my company protecting a bad employee?

I work at a small child care center that is apart of a larger company. There are some changes that have been happening that honestly don’t make any sense. The latest one involves a woman we’ll call Lauren. Lauren has been with the company for many years and holds a Masters in child development. The problem is Lauren doesn’t seem to know the first thing about helping children, health and safety, or procedures. She was even written up 3 times in one month by our higher ups for violating the children’s health and safety. She was a head teacher in her other room and now they want to move her into my room still as a head teacher. I was told to “help her out” and “show her what she needs to do”. I have only been with the company for 1 year. Shouldn’t she know what to do? The classrooms are the exact same. Same schedules, same procedures the only thing different is the kids but when I try to tell Lauren about the kids and their personalities she ignores me. Now she might get another write up because she deliberately left 4 children on our side of the yard ( it’s one yard split with a fence down the middle) without any teachers on that side with her back to the children. What really confuses/ annoys is that the company decided to get rid of one really good teacher in favor of Lauren. Why are they protecting someone is is a danger to the kids and the center?