I think — as a Remainer who remained so hard I responded by moving to Berlin — that "why" is "because it was a referendum and that's how those work".
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.
> which may be easier with the truth but is also much harder when insulting half the electorate
I'm not sure this is correct. In both the Brexit campaign and the Trump election, the winning side spread insults freely, whilst meanwhile spinning a narrative that the other side were talking down to their supporters.
In both cases, the more aggressive and less truthful campaigns won, and the more "proper" campaigns that tried to reach out actually failed.
Being bolder seems to work better in the current political climate, not pussyfooting around being safe and trying not to insult anyone. I wonder if refusing to apologise and doubling down on the "garbage" comment would have worked better.
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.