Not everyone's a rocket scientist, whether of the literal or the metaphorical variety. All any of us can do is make the most of the intellectual abilities we have. No matter how smart you are, you can only know so much. Even the brightest among us must remain ignorant of that beyond their ken. We can seek to expand our realms of our knowledge. Expanding human knowledge is perhaps the noblest of all pursuits, but the limits of time and space set definite boundaries to that which any of us can know.
Some among us eschew both intelligence and knowledge. They choose to use what intellectual abilities they possess to preserve ignorance, both their own ignorance and the generalized ignorance of our species. Apparently that kind of aggressive stupidity has been around for centuries. It's still with us.