What nonsense is this ..?

I sympathize with your views. To me those nobles were little more than brutal gang lords, not noble at all in actuality, who enforced the respect they demanded by force of arms and terror, the only freedoms they were concerned with were their own. Many of these families cling to power to this day, less than a hundred years ago their influence and power was still considerable. It does, or could, remind us that with commitment and determination that if "we" stick together we can change the policies that our leaders deem is best for us. Celebration might be the wrong word but acknowledging that event isn't so bad if it denies dictatorships or absolute rule, it marked one of the events that lead to change. As for costs it depends how much.