But why? Why is it the job of the people who are on the side of established truth who have to understand the views of the fantasists? I saw more "disparagement" from the pro-Brexit crowd than the Remainers. Why isn't it their responsibility to understand the realist position?
We told them Brexit would be a disaster. We were told we were scaremongering. It went ahead anyway, and it turned out to be awful. It was a stupid decision, and it was terrible judgment.
Why can't we tell people that some proposals are stupid? And why can't we tell people after the fact that they made a stupid decision? How is it our fault that they make bad decisions?
It's not sufficient (or necessary) to be correct to win in a democracy, winning requires being convincing, which may be easier with the truth but is also much harder when insulting half the electorate.
Even when it's very tempting afterwards to say "we told you so".
As for how to be convincing… dunno. I'm much more comfortable with computers where I can google the errors.
Immigration is also a big factor in the Conservatives' defeat in the general election. People felt cheated as immigration hit a record high and voted Reform UK, which handed Labour a huge majority despite actually getting fewer votes than at the previous election.
So it's quite extraordinary to see the comments here with zero reflection on why all of this happened. This is the real, dangerous divide between the well-offs in and around London and the rest of the country.
I have read that the two main issues on voters' minds in this American Presidential election were immigration and the economy, so result is not very surprising.
"High" migration likewise had nothing much to do with EU membership, as the government demonstrated precisely by following Brexit with, as you say, record high immigration.
One of the other famous big concerns Leave campaigners had was the cost, which famously became the £350 million a week on the side of a bus. This number was even called out as a falsehood at the time, but it was believed by enough to make a difference.
Remainers were unable to convince the majority that the benefits of EU membership was worth the cost, financial or otherwise, regardless.