“the EU was set up to tie nations together so tightly they could never afford to go to war again.”
If you mean they could not afford to go to war because they had insufficient funds then it’s certainly achieved that aim. The exception, of course, is Germany which has been running a current account surplus well in excess of EU rules for many years because it refuses to distribute its wealth across the poorer euro nations. Coincidentally, if my history serves me well, it was that very nation that was the principle cause of the two world wars.
However, if you mean they could not afford to go to war because they were inextricable linked you may be surprised. The EU has brought untold misery on millions of people and many of the poorer nations blame Germany for their plight. It would not take too much of a crisis – especially where the illegal movement of people across the continent is concerned – to kick off a few minor skirmishes, as was demonstrated last summer. And we all know what minor skirmishes can lead to.
“I sometimes wonder if they're so anti-establishment because they are low achievers and have a bit of a chip on their shoulders.”
Many are not anti-establishment, Zacs. They are anti-EU which is an entirely different thing. It does not do to lump the two together, especially when you suggest, by connotation, that those who are anti-EU are low achievers with chips on their shoulders. Many people who are anti-EU are considerably high achievers and have nothing which might cause them to have a chip on their shoulder.