two World wars
As you say, Britain and Europe have been plagued by a terrible history of destructive warfare. The men who founded the European movement had just lived through the worst war the world has ever seen. The older ones had also lived through the second worst war the world has ever seen. Nothing was more important to them than preventing a recurrence. They have had tremendous success.
And you look back to the days of millions of dead with warmth and nostalgia.