Because these predominantly sheltered, pretentious, middle class Remainers used to getting their way and having their views and opinions validated repeatedly by the popular Left-wing media, who were so smug and self-assured in the likelihood of victory, were given a hard slap in the face by the long, unforgiving c**k of reality.
But first comes denial, then anger, bargaining, fear, and finally, acceptance. They'll get over it.
It's a small taste of what's to come if Trump wins.