I was thinking earlier about why it is that Brexit hardliners seem so determined to see conspiracies by remainers as the reason for Brexit failings and I think it's a case of projection again. Whilst I oppose Brexit, had it delivered on the promises I would have had to begrudgingly admit I was wrong and would have embraced the benefits such as lower food prices, higher wages etc etc. I think this is fairly consistent among remainers, opposing the idea but that was due to thinking it would fail rather than actively wanting it to fail. There was no desire to sabotage any opportunity that it might deliver a better life.
Brexiters on the other hand didn't seem to hold this view (the hardliners that is). People like Farage et al actively sought to ensure the EU failed and were actively sabotaging it. For example he complained about the UK fishing arrangements and yet, when he was in a position to negotiate fishing arrangements on behalf of the UK, he turned up once to splutter a load of nonsense and then never bothered to turn up again, effectively meaning Britain had no serious representation on that issue.
As the hardliner Brexiters knew that they were actively sabotaging the workings of the EU whilst within it, the assume everyone is like them and therefore any failing of Brexit must also be because of sabotage.