Not only do the posters in these forums prove it, research also proves it:
"While hardly comprehensive, the test "is considered a good indicator of general cognitive ability," the researchers note.
After taking into account participants' party affiliation, the researchers found intellectual ability was a strong predictor of attitudes toward the two major candidates in 2016. Specifically, they found "clear negative relationships of verbal ability and education with attitude toward Trump."
In contrast, they found "weak, nonsignificant relationships of verbal ability and education with attitude toward [Mitt] Romney" in his failed 2012 campaign. In both elections, higher levels of education and verbal ability were associated with support for the Democratic candidate [Barack Obama or Hillary Clinton].
"Support for Trump was better predicted by lower verbal ability than education or income," the researchers add. "Our analyses indicate that support for Trump was less about socioeconomic standing, and more about intellect."
Ganzach and his team note that Trump, on the campaign trail, expressed his opposition to both socially liberal beliefs (such as support for abortion rights and opposition to racism) and fiscally conservative beliefs (such as free trade). Both sets of beliefs have been linked in past research with higher cognitive ability, so it makes sense that their appeal would be largely limited to those who score lower on such measures.
This research adds to the rapidly growing list of findings attempting to explain why the American voters (although not a majority) supported a candidate widely viewed as lacking the qualifications or temperament to be president.
While economic anxiety has been largely ruled out as a likely explanation, studies have pointed to whites' fear of declining social status in a rapidly changing society, as well as racist and sexist beliefs, tribalism, possessing an authoritarian mindset, and even being prone to anxiety, and thus susceptible to Trump's fear-based appeals.
Ganzach's findings align with those of another recent study that found Democrats who crossed over to vote for him were the least likely demographic to engage in analytical thinking. This may be because, in many cases, they just aren't good at it."
https://psmag.com/news/trumps-appeal-to-the-cognitively-challenged