On the contrary we show great understanding. Understanding that people dislike realising they were gullible in believing in Santa Claus, resentment when this is pointed out to them and entrenchment in maintaining that they were right all along and everyone with a different opinion is utterly wrong.
Remainers knew what they were voting for and, based on history, also knew that the EU would adapt because of internal pressure from its members eg Italy. GB could have influenced that change from within.
Leavers could not know what they were voting for - other than a slogan - because even their flag bearers,Gove,Johnson,Davis,...had no idea themselves but were driven by political ambition.
As is now abundantly clear.
But we are where we are and "could have,should have,might have,if only,..." is as futile as arguing about whether or not Britain should have engaged in the Great War - a not irrelevant reference point- so perhaps we should look at it all again in a hundred years when things will be clearer?