You do realize that not all professional children's storytellers and performers are drag artists, right? Some of them happen to be drag artists. Which is understandable, since drag queens are often flamboyant, entertaining people who love dressing up and putting on a show. Why shouldn't some of them make a living entertaining children like anyone else? Plus it's a good way of exposing kids to the idea that all kinds of people exist and that within certain obvious common sense boundaries, it's fine.