An ethics class doesn't make you ethical, no more than a criminology class makes you a criminal. Ethics isn't about making you ethical ( though it may ), it's about studying the history and principles of ethics. It's about giving you the foundation to reason about ethics.
Try the trolley problem. Is it okay to divert a trolley to kill 1 innocent person to save 10? What about 5? What about 1? And this is just an abstract thought problem. Now try war, nukes, abortion, death penalty, etc. Everyone has a simplistic and superficial idea of ethics. An ethics class helps you develop a deeper and broader understanding of ethics. To develop the what and why of ethics.
Try the trolley problem. Is it okay to divert a trolley to kill 1 innocent person to save 10? What about 5? What about 1? And this is just an abstract thought problem. Now try war, nukes, abortion, death penalty, etc. Everyone has a simplistic and superficial idea of ethics. An ethics class helps you develop a deeper and broader understanding of ethics. To develop the what and why of ethics.