Because you won't function in life as well if they don't teach you from right from wrong, like they will give up and not try, there never get a job possibly, and they won't have kids. That will ruin there if because there not trying and not accomplishing anything. Possibly.
There should be a class in all schools that teach basic human ethics as parents often get these so terribly wrong. The recent shootings can be the result of children learning poor ethics from their parents and chosen peers. Properly trained teachers/councilors should exist in the school to teach and demonstrate ethics.
Teachers may not always demonstrate good ethics, they need to be monitored by the trained ethics teacher so as across the school, all teachers demonstrate good ethics. In such an environment the students feel such ethical behavior is very natural and thus it becomes a form of normality.
I think its a good idea and it SHOULD be taught, but really, its not something that can be done correctly. To teach a child right from wrong is a good thing to do, but difficult given that everyone has different moral... Take, a touchy subject i know, but abortion... I'm pro choice and in my opinion i think that is "right" but i also think pro life is also "right", but pro choice is "MORE right". Because there a plus and down sides of both, pro choice has the bad side of your killing an unborn baby and pro life has the bad side of your forcing a mother to have a baby she doesn't want.... So it would be good to teach right from wrong, there just isn't a good definition of what that is
While I fully believe that children should be learning the difference between right and wrong from parents at home, it is also the duty of teachers, and all adults involved in children's lives to teach them good morals. There is an old expression that says "it takes a village to raise a child" and I am a full supporter of that idea.
Teachers cannot tell students what is right and what is wrong, there are too many diverse viewpoints on morality. What they can do is teach the various theories on ethics (e.G. Consequentialism, deontological ethics and divine command theory) and allow their students to choose for themselves. Philosophy has no right-and-wrong answers, only opinions.
Teachers should not teach students the difference between right and wrong primarily because there is no objective way to teach ethics. Students should learn ethics from their parents when they are young, and then develop them further as they grow up. Teachers could demonstrate how ethics are different across multiple cultures, but they should not teach students what is right and wrong.
A teacher is there to teach academic lessons. I think it is okay for a teacher to tell children simple things like no hitting or making fun of kids. That is all things that may happen in school, so therefore it should be addressed to keep children in a healthy and safe environment. However, outside of that no. There are many things a teacher may see as right or wrong that a parent does not agree with. A teacher should not be teaching children morally, religious-wise, or about their views on society, etc. A teacher after all is just a person and there idea of right and wrong is colored by their own life experiences. Because it may disagree with what a parent wants their child to be exposed to at a certain age, or they may not agree with a teacher. It can raise conflict.
I do think that this does naturally comes up over the course of the teachers day when they discipline students for various infractions, but I don't believe they should set out to teach right and wrong. Many people have differing opinions on morals and I believe that they should stick to teaching the material.