“But I have a question - and not that I don’t think Brexit is a good thing anyway - but didn’t a common market like the EU diminish the historical reasons for war?”
While that certainly was the intent, and it did work well for a while, having a common market is a lot different than having to live under a foreign, unelected, unaccountable, left-wing dictatorship based in Brussels.
In other words, what was to be a trading block was taken to the next level, and that’s when people started saying enough is enough...as Britain has said, and other people in other countries are also saying.
So they went too far....too bad.