It's not unpopular and more so true. Religion is anti-intellectual, and the main abrahamic ones double-dip hard on it. If you ever tried arguing with a religious person about faith, it's incredibly obvious how impactful it is on their critical thinking.

Capitalism also prefers anti-intellectual thinking because it makes people easier to manipulate and exploit into accepting shitty conditions and supporting the system. I think a large cause for the lack of critical thinking and self-reflection is because too many people live a very self-centred life where they consider themselves superior automatically and never take the time to question their beliefs, or if they do, refuse to face contradictions because it's harder than staying the same.