>We're teaching our children to respond appropriately to conflict—in the situation above, either one of them can deescalate by approaching the conflict reasonably. He could have avoided it altogether by asking nicely for her pencil. She could deescalate by recognizing that he really wanted her pencil and making a trade that they both are happy with. It's hard for them to do because their escalatory actions feel more immediately effective at bringing "justice", but they don't work out in the long run.

Again you're using an example of two children who are equal in power dynamics. Now try having a child deescalate an angry adult. Most people would not find that a reasonable request.