It's not just America - see the responses after Brexit as well. The major claim seems to be that most people are just not intelligent enough to have voted correctly.
After Brexit, the smugness continued. Remain supporters took the campaign for a revote that got millions of signatures as a sign people were regretting, but obviously the signatures mostly were from people who had voted to remain.
Still, "they regret it already" was the message spreading throughout Europe for a while. I recently saw some research stating that a very small percentage had changed their mind about the vote, and they came more or less equally from both sides. So no, no significant regret noticed.
Not sure why I'm writing this. It just seems that the people seeming to vote rationally are completely irrational when it comes to judging the other side. Did we collectively lose the skill of empathy?
We need to understand this or we'll be repeating these mistakes forever.
I've heard this argument but from the small sample of brits I know(I'm South African), those who voted Leave are highly educated. Two MBAs and an actuary. This trend seems to influenced by something other than "intelligence".