The issue is that the clown Cameron decided arrogantly to have a referendum with no terms of reference, then we had bad faith actors like bozo and farage refusing to enter into meaningful dialogue as to the terms of what and how any Brexit might look, with meaningless three word slogans like "Brexit means brexit" and when (occasionally) challenged just retorted to "project fear".
IF Cameron hadn't been so arrogant, we could have had a referendum that said that if a majority voted to leave, a choice of three withdrawal agreements would be drawn up, and the electorate given the choice.
If Her Majesties Media had driven home the point that it would certainly have meant the Irish Sea Border, about 200,000 in Northern Ireland, and I would say quite a few from the Dumfries and Galloway and Ayrshire areas would have flipped, likewise the need for visa'sif you wish to reside within the EU would have flipped quite a lot of the "exiled in the Costa's"
Though I agree that May triggering Article 50 was idiotically stupid.