Coaching classes do not exploit students it helps them learn and get the one on one attention they may be needing. Some people need someone to really explain a problem to them, or really show them how something is done and they are just to nervous in large groups and such.
Coaching classes done properly do nothing but support student development. Coaches can learn best practices as far as student safety, well-being, and training. This allows students to be less likely to be involved in injuries as well as removing them from the game once an injury has occurred. A better prepared team also enriches the fun and learning for the student's on the team.