The Three Forces

There once was a village in a valley between two mountains and next to a river. One mountain was known as Attackus, and the other, Defendan. The river separated the two, and was known as Mediator.
It was in their tradition that whenever there was a dispute, a point of debate, or even the smallest disagreement, they would bring the two parties to either mountain, through randomly drawn lots, and someone who was unsure of the matter to a raft, in the center of the river. Then it would begin. One of the group on Attackus, would throw a folded slip of paper, either with or without a mark on the inside, downwards towards the raft, where the unsure one, would decide to write another mark or not on the inside, without unfolding it. If there were either one or two marks it would be deemed that the Mediator agreed with the Attackus, and henceforth right, otherwise the Defendan was right. This system was considered perfect until one day, the unthinkable happened. Someone did not agree with the judgement.
Thomas was a young man who disliked that the store did not give him a valued costumer discount. And so, he stood on one mountain, which happened to be Defendan, and the store-owner on the other. The ritual was done, and both the store-owner and the undecided party both marked the slip. And so Thomas decided to cast question on the tradition, in the hope that he could win in the revolt. But understandably quite a few figured out what he was trying to do. But others did, side with him, even though they too knew what he was trying, they also had lost in the ritual, and thought they could get in back through this revolution.
And revolution there was, fighting on the streets, in the market markets, and at the town square.
And so everyone was debating on the issue, and couldn't find a way to solve it. As they obviously couldn't use the usual method, and anyway, there was no one impartial on the matter to be the Mediator. What could they do? Their whole system was collapsed with a single movement. Had their fine village been destroyed in a single strike, or was there a solution? Was their village ever truly fine, considering how easy it was to bring to its knees?