Ireland has a long sad history of being exploited by outsiders, mostly Britain. Why any of them would not want to be a unified independent state escapes me. I get that religious divisions run deep, but Geez— why stay on the UK plantation?
At one point the UK had better living conditions than the Republic of Ireland which was a deterrent to Northern Ireland wanting to unite with the Republic. But apparently the per capita income in the Republic is now higher than in the UK. So maybe the main reason to stay apart is Northern Irish Protestants not wanting to be in a Catholic-majority country.
The bigger question is why they want to be on the EU plantation, under Teutonic rule via the Brussels proxy.
At least in the UK, they actually had voting rights, and those being the same rights the American colonies sought and were denied before they struck out for independence. Don’t take the long-standing narrative as absolute truth.