The Bosnians would beg to differ on this point [1]. It was not so long ago, and yet it all started on very similar terms as Brexit: the breaking of Yugoslavia into multiple parts who wanted different things (Serbia vs the others) via referendums reminds me a lot on how Brexit started.
I don't think we're at the point where entire factions of people hate each other enough to start, support and sustain an all-out war, but then again with MPs getting daily death threats (some even actually getting murdered [2]) and the political dialog shifting towards low-levels of populism, it's tempting to think that the scales might tip at some point.
Maybe one solution would be to have a county-by-county referendum, where each county in NI gets to decide whether it wants to stay in NI or instead join Ireland. This would make NI smaller, but would concentrate the UK loyalists in it, and the number of Republicans (the ones who want to rejoin Ireland) would decrease a lot (many would be in the counties that would leave, which are probably mostly right on the border, and some might even move), so maybe re-establishing a hard border would be more palatable then.
The Northern Irish 6 counties did not want to unify with Ireland when Ireland was born in 1919. Those 6 were the protestant majority counties, who wished to stay with the UK.
Changing demographics and birth rates over the following century, increasing secularisation in the Republic, and increasing numbers who simply don't care about religion makes that far less of the issue.
Just as those ruling in London no longer see themselves as Norman French, or in my UK county Danish.
But in ireland it is not only about the english living in north ireland, but more about the irish living there. It was more about catholic vs. protestant.
Not so easy to dissolve, but I hope the last blood happened long ago enougj for both sides to forget and move on, even if england messes up the deal amd the border becomes an issue again.
This is debatable. It was very close and the large numbers of English retirees in parts of Wales that made it seem that Wales voted to leave. Brexit is very much an English project.
Citation: https://www.theguardian.com/uk-news/2019/sep/22/english-peop...