"Why should I think about this?"
Questions of this kind often reflect a misunderstanding about what ethical reasoning is. Students might think they are being forced to make judgmental pronouncements about others or that they themselves are going to be made to feel guilty about what they do.
What we are asking students to do in the study of ethics is to engage in ethical reasoning. When we are answering questions about what is the right or wrong thing to do, we are attempting to give reasons that any reasonable person can accept as reasons and build arguments in order to support our ethical conclusions.
There are acceptable reasons and unacceptable reasons.
Unacceptable reasons include arbitrary reasons, prejudicial reasons, and appeals to questionable authorities (God, society, leaders).
Acceptable reasons include reasons based on the kinds of considerations that reasonable persons can accept, discuss and debate, and support by larger ethical arguments or frameworks.
When asked why it is wrong to cheat on an exam, answering, "Because my second-grade school teacher said so" is not a very good reason. Saying something about values such as honesty, integrity, and fairness to others would be better reasons.
Ethical reasoning does involve making judgments, but judgments that tend to refer to rights, obligations, benefits to society, fairness, or specific virtues. Ethics often refers to those standards that impose reasonable obligations to refrain from behaviors such as from rape, stealing, murder, assault, slander, and fraud. Ethical standards also include those standards that enjoin virtues of honesty, compassion, and loyalty. These standards are supported by consistent and well-founded reasons.