I find that people from both sides of the argument focus too much on individual things that they see directly or which affect them directly.
Every major event causing civil upheaval in history has brought both great costs and great benefits. The black death of 1348-50 (in the UK, slightly different timeframes elsewhere) was the greatest pandemic in human history. In England (specifically, I don't know if it applies to other parts of the UK) at least 1/3 of all people died, many more in famines that followed due to a lack of agricultural workers. But in the decade or two that followed, the old serf structure began to collapse, workers wages spiralled upwards overnight, major advances in milling and weaving technologies occurred to help offset the worker shortages. Many new opportunities opened up for the survivors who would otherwise have been doomed to a life of serfdom. So was this event a good thing or a bad thing? It was both - major upheaval always brings opportunity for those prepared to grab it.
Likewise, think about the massive changes in social structure and technology that occurred during and after both WW1 and WW2. Noone would choose to get those changes through war, but the net effects of both were massively beneficial for most, especially those at the bottom of the pile.
At the time of the Brexit vote when there was lots of talk about the economic costs and how it would be madness to vote leave I always went back a one analogy:
Imagine a successful couple in London, perhaps traders, senior lawyers, whatever. Salaries and bonuses most could only dream of, Perfect home, Perfect children, all in perfect private schools. Life's great right? Except something doesn't seem right. They start to think how life would be much better out in the country, they dream of being hill farmers in Wales. They do their research. They know it will be hard. Long hours, bad weather, little financial reward. But somehow it still seems right. They can't really judge whether it is the right thing to do or not - there are way too many variables to know how things will actually turn out - sometimes you just have to prepare as best as possible and then just leap into the unknown.
Ultimately when you make those kind of decisions you know there are massive costs, there will be massive changes, it won't be easy. But there will also be new opportunities, new adventures. Would it be the right decision for everyone - of course not - but that couple, at that moment, feel it is right for them. It is down to them to make the best of their decision.
That's how it was with the Brexit vote. You can only vote for what you feel is right for you. You can of course believe that your choice is also good for others, but they are the ones that have to work out how to make it work should the majority agree with your view.