But they were voting on joining a common market like the rest of the U.K. They too were sold down the river by Germany and France who had their long term goal of ruling Europe.
Back in 1972 it was the Common Market not a European Union, that was shoehorned over the years by greedy politicians.
It’s a persistent delusion among Brexit supporters that every EU country is about to leave, and that they face the imminent collapse of the Euro. I’ve been reading this stuff since well before the referendum. No one has and I very much doubt any of them ever will.