Teaching to say sorry, do we need to?

My answer would be no.

Why you ask?

I think that children will learn what they need to learn in this world without being explicitly taught to do so. Unschooled children learn to read and write without being explicitly taught to do so, just by wanting to. Sure, they will ask questions, but when they get those answered, they will learn it. My own children are just an example of that. My 11yo daughter is speaking, reading and writing in three languages. She has started messing around with the fourth in the meantime. When an average child can learn that, just on their own, then I do think people can really trust their children to learn to learn the correct word use of the society as well.
I think it would be quite an insult to their intelligence to think they wouldn't learn to use simple words like that when they can learn whole languages, don't you? Besides it also shows no faith in your own child to be able to learn as it is.

I have read about the Yequana, there people do not consciously teach children stuff. They expect children to just grow up and do their thing within the tribe. Obviously it has worked for a very long time, because they haven't changed their ways. It has made me wonder why the ways have changed in our society. I don't think it has much to do with whether children learned or not, probably more with a certain way of not trusting children to learn. These ways are on in the western civilized countries this bad, not in others. I guess people don't have time there to bother with these things, they have more important things to do, like make sure they get food.