It's important because ethics is a really complicated subject built on thousands of years of study and thought. It's worthy of being taught by an actual scholar who dedicated their life to understanding the field.
Parents can teach right and wrong, but they seldom teach about things like utilitarianism or hedonic treadmills.
In any event, the poster I replied to also included "morality" alongside "ethics", which is why I suggest it's not as cut and dried as you imply.