My family vacationed in Germany only 23 years after the end of the Nazi horrors. And I was in Germany, living with them, visiting family and making long term friends only 35 years after the war ended. Bombs we dropped on Germany are still being found, despite the economic and urban development. In France and Belgium, every year someone uncovers unexplored ordnance from WW1, frequently containing chemical munitions, so the cleanup there is still ongoing after 100 years.

What is your point? Wars take a long time to clean up. Generally, people want to restore friendly relations after a war. (Unless the victor is France.) Even our own peace treaty with Germany ending WW1 said the intent was to restore friendly relations between the two governments and their people. The Paris Peace Accords said much the same thing. The Vietnam war is just as much history as either World War, and so too the Cold War. We SHOULD have friendly relations with Vietnam and my only surprise is that progress to that end has been so slow.