It's well documented that Americans are, on average, quite undereducated. And it's also quite well documented that most of the people that vote for Trump are poorly educated.
So, not stupidity, no. But a lack of education can look similar.
I'd argue that anyone blandly categorizing dozens of millions of people who vote for a candidate (including many from communities of color and among immigrant demographics) as just uneducated ignorants is themselves overwhelmingly ignorant.
You can be against Trump for many good reasons, but a good look at why he won is about much more than just deriding his supporters as ignorant.
I'm against Trump for all the obvious reasons, which there's no need to enumerate here.
Being against him doesn't explain that an openly fascist craven liar just won the US presidency. A poorly educated population does.