That really is a mistaken belief. “Theory” in science doesn’t mean what “theory” means in everyday parlance.
However, the real question is, if the theory is so well established, why does it matter if anyone believes in it or not? Do we go around quizzing people as to whether they believe in the theory of electromagnetism or the laws of thermodynamics? If it’s a true description of nature, then it doesn’t matter whether non-scientists believe it or not. Belief only matters if you are trying to promote a belief system.
Excellent point.