I understand that you're angry and you want someone to blame, but in my defence, I'm not as obstinate, naive, or deluded as you think I am. My reasoning on Brexit is fairly considered and complex; a large part of me wanted to vote remain and I hesitated in the polling booth. In the end, after many months of what you would call extensive 'introspection', I gradually shifted from a strongly pro-EU position towards favouring leaving the EU. All that introspection and reasoning doesn't mean that I can't still be wrong, of course; I constantly question whether I've misjudged the evidence in front of me and I can't be certain that I haven't. But I'm a long way from an uninformed optimist; indeed, I don't know it for sure, but I have a hunch that I'd comfortably fall within the 75th percentile or higher of what you might call 'informed pessimists' on NeoGAF, at least when it comes to the study and review of public policy in the British and European context.
What would it take to make me think that Brexit is/was a disaster for Britain? Clear, substantial and permanent declines in economic output ('clear' meaning a consensus of accumulated and decisive evidence, not isolated data points or changes within margins of error; 'substantial' meaning severe decline relative to previous UK growth rates and European comparators; 'permanent' meaning declines across a 5-10 year period and beyond as I think we need to measure Brexit beyond the transition years, which are not likely to reveal the real long-term impacts on UK growth and productivity). I would also accept serious, substantial and long-term declines in public services (operating costs, quality of outcomes, efficiency, and so on - as much as such things can be measured and linked to Brexit), sharp and sustained rises in inflation and the cost of living, declines in skilled immigration, declines in start-up growth, declines in foreign direct investment, declines in national productivity, sharp and permanent declines in imports and export industries, and so on, as supporting evidence.
I also recognise that there have already been some negative consequences of Brexit; the depreciation of GBP, the mutilation of Toblerone, etc. And there are worrying indicators of discontent in financial services, among doctors and nurses, and high-skilled European professionals, and in other sectors. But so far I don't think any of these things can reasonably be said to amount to, or have yet materialised as, full-blown national disasters at the present moment in time. In other words, I think that if Brexit is to be a disaster, I don't think that disaster has directly impacted us yet. None of this is good but we have yet to see how these things will play out in the long term. It's theoretically possible that arrangements may be made to mitigate damage in this sectors and areas; that the banks will offshore some Euro clearing jobs but keep the bulk of the work in London; that Hunt's mismanagement of the NHS is a seperate issue from Brexit and that conflating the two will not help us fix the problems arising from either; that new systems will be able to attract high-skilled talent from other continents to offset losses from Europe.
I'm not a naive optimist. If Brexit is a clear disaster I will need to accept it. But I can't yet say that I was wrong about Brexit because it hasn't happened yet; it's a vast, complex and entirely novel piece of public policy and it'll be some time before I'm able to say whether it has, on balance, succeeded or failed. I'm not going to explain why I voted the way I did, because I don't think anyone here (including myself) is going to change their mind on this, so it's a pointless argument. But I did want to chip in from a leave perspective.
That's a merry post, but I'm still to see a valid reason why leaving the EU is better for the UK than staying, all I see are negatives.