WrongTrouser, I'm the last person to defend non-voters, but as someone else has pointed out, even if 100% of the population of Northern Ireland had turned out to vote remain, they don't have a big enough population to have influenced the result. Not to mention the fact that Northern Irish MPs are conspicuously absent from Westminster politics. People in Northern Ireland are to all intents and purposes not represented in British politics.
In many ways, it is not particularly surprising if voter engagement in Northern Ireland is low, and the fact that the turnout was as high as it was is probably a good indication of how significant this could be for Northern Ireland. (And as some posters have already pointed out, there will be people in Northern Ireland who voted leave precisely because they want Northern Ireland to be reunited with the Republic.)
For what it's worth, I don't think it's realistic to expect leave voters to come up with the solution here. I do, however, hold leave campaigners responsible for encouraging people to vote leave without giving any attention to important issues such as this. We all know that Nigel Farage is a nasty little racist, and his campaign tactics should have surprised no one. It's also obvious that Boris Johnson and Michael Gove are just uber-Tories who probably didn't care whether we stayed in the EU or not but saw campaigning for leave as a way to advance their political careers.
But when you have Theresa Villiers, the Tory Northern Ireland secretary, and Kate Hoey, a prominent Labour leave campaigner who is from Northern Ireland, attempting to shut down the debate by dismissing any suggestion that the Northern Ireland peace process could be at risk, that is something I find shockingly irresponsible.
In the same way, I think Priti Patel and Gisela Stuart were flaunted as examples of "why the leave campaign cannot possibly be racist or xenophobic - look at our lineup".
I'm particularly pissed off with Gisela Stuart, a German immigrant who exercised her treaty rights to come and live here the year after we joined the EU, has benefited from free movement all that time, became a naturalised British citizen, campaigned for leave and is now expression "concern" that EU citizens living here are now facing an uncertain future and may find themselves being used as pawns in a political chess game not of their making. Well, no shit, Sherlock.
But you're right, I don't think it was really reasonable to expect the average voter in England or Wales to appreciate the significance of Brexit for Northern Ireland, and even if they did, most people vote for what they think will be in their own interests and don't care so much about people they don't know who live in other places. That's human nature. But it's just another example of why the referendum was a bad idea. Brexit could have very significant and harmful consequences to a number of minority groups and their lives could be very seriously affected, thanks to the actions of the majority, who were (a) not very well-informed and (b) acting in their own interests.