It’s because there are tons of laws and regulations regarding minors in school, and administration tends to be homegrown (initial expertise in teaching) rather than explicitly developed to navigate the social, political and legal landscape. I’d wager that more than half of those positions are “best practice” staffing decisions in response to this landscape. A handful might also be due to expressed needs and wants of parents. Likely wasteful overall, but students, teachers and families would likely feel the impact and not be satisfied if any positions were axed.