Technically correct yes but there's no moral or philosophical argument being made there. Yes, most people in the UK voted to leave and yes, most people in Northern Ireland voted to stay. But factor into that the large chunk of Northern Ireland that doesn't even want to be in the UK and it is no longer a matter of simply rattling off facts. Northern Ireland is an artificial entity created to serve an agenda, its existence an excercise in gerrymandering. Peace in Northern Ireland was secured by clawing some power back from the much larger and more powerful UK mainland, and the UK removing Northern Ireland from the EU against the will of its people is a betrayal of both the letter and the spirit of that peace deal.
I don't believe we can call ourselves a democratic union of nations if one of those nations can act against another without the consent of its people. This kind of behaviour is exactly why people voted to leave the EU in the first place, and we will not settle the matter by acting in the same way now.