Tolerance always has a limit. And the one thing any tolerant society can never tolerate are intolerant people - because they will destroy that society. Trump and his followers are the very definition of intolerant.
Thus the "if you are tolerant, you have to tolerate me" argument is often used by aforementioned nutbags or internet trolls, and I very much hope you fall into the latter category.
And regarding stupidity - sadly there is no mechanism to ensure that it is fairly distributed. A less than ideal public school system paired with the propaganda of media conglomerates can easily result in a society with half the population considered "dumb" (not really stupid, but brainwashed / uneducated with a lack of critical thinking and/or a lack of basic scientific knowledge ...) - but I would not judge the US population that quickly. Trump is probably also a symptom of the broken US democracy.
I would argue humans often have a world model that is too coherent. If you ask a flat earther about their beliefs they will always argue that the earth is flat and evidence to the contrary is manufactured or interpreted wrongly. That is a completely absurd world model, but perfectly coherent.