The bold part is almost true, but not quite. I have solid basis for believing (not assuming):
- Democracy fails without informed voters ["The cornerstone of democracy (is) an educated electorate." Thomas Jefferson]
- British "Leave" voters were largely uninformed
- Wily political operatives & parties prey on the poorly informed
- When wrong on the data, political parties must first convince the people not to trust science, education, or the mass media. Ignore the facts.
- Step two is to turn those people toward biased sources for "knowledge"; essentially, you make conspiracy nuts out of them
- Step three is to constantly distract the people with irrelevant, salacious things, particularly if you can get them angry about it, at least until they vote
- There is no step four, since if you solve the problem (real or supposed), they no longer need to keep voting for you
- Historically, causes embraced by the hateful, angry and/or stupid mob lead almost universally to tragic or merely poor results
- To your point, yes, I do believe that leaving the E.U. will harm the U.K., and certainly Europe, and possibly the world, at least for awhile
- Embracing diversity is a wise, good thing
- Racism and sexism are evil
- Xenophobia is akin to racism, but for ultra-nationalists
- All the -isms are merely forms of prejudice
- Prejudice means making decisions without having the facts, based on appearance and hype
And so we end back up at the first point.
The rest of your post has problems, too. The ignorant masses are rarely correct about much, except in understanding their own physical needs. As soon as they begin to satisfy them, they get into trouble. Knowledge > Ignorance.
We agree that elites aren't always right. The top 0.01% of the rich are a super-duper-special interest group, so all this rot about Trump not being beholden to special interests is idiotic. He is an elite, financially, despite not being as rich as he claims.
The answer is not to support any one party, or certainly any one candidate, but to follow the data. Sir Arthur Conan Doyle's Sherlock Holmes famously said, "Once you eliminate the impossible, whatever remains, no matter how improbable, must be the truth." Once you find the truth, no matter how inconvenient, you must follow it, even if it means your convictions are split, and some of your friends desert you.