As Jack mentioned and as Eliezer repeatedly said, even if a certain question does not make sense, the meta-question "why do people think that it makes sense?" nearly always makes sense. So, to avoid going insane, you can approach your ethics courses as "what thought process makes people make certain statements about ethics and morality?". Admittedly, this altered question belongs in cognitive science, rather than in ethics or philosophy, but your professors likely won't notice the difference.