It's easy to say that when you're an outside party who doesn't understand or care about the underlying issues. Not to minimize the issue with the metaphor, but have you ever fought with a sibling or someone else at school and your disinterested parent our authority figure told you to both to stop without addressing any of either of your underlying problems? How well did it work?

Pretending that "just stop it" deals with the realities of a complex history of real grievances and legitimate causes for anger and retribution on both sides is the most magical of magical thinking, and it doesn't help that third party negotiators usually start their peace proceedings by learning NOTHING about the history of distrust and anger building up over decades, picking a side to ride or die with, and then declaring the issue fixed as soon as someone signs an agreement.