You teach them to share because being selfish comes very naturally. Kids that don't share are very noisy and parents are interested in quiet, not justice.
I completely agree with you. If sharing does you no good in a certain situation, then don't share in that situation. It's common sense and in my opinion what we should be teaching our kids.
Yes. This is why I think that the way we teach our children nowadays (teaching them morals not logic) is going to hurt them in the end.
That sounds like a good idea. Teaching kids to make intelligent decisions, not follow orders.