Anti-intellectualism is due to the rise of fascism, and fascism is due to the lack of knowledge/understanding - let it be intentional or coincidental.

Human brains are wired for two things, from birth:

• fear of the unknown, to help survive. this is why you fear the dark as a child, and why you create circles of "distance of understanding" - the further something is from you, the more afraid you are of it. And this is the core source of tribalism.
• in lack of knowledge/understanding, gravitation towards those confident in their knowledge, even if it's bullshit (populism). Simple, easy to understand answers to questions you have, especially if they fuel the underlying tribalist hate, will be more successful in convincing people than well formed, reasoned solutions.