People have beliefs and goal functions (religious - obey God; love / protect spouse and family; acquire money and power; maintain health and increase status, and positive image of self.)

A powerful brain is like an engine with more horsepower and torque - like a fast car, if you're going the wrong way it will just get you there even faster.

It's very human to be unwilling to admit error or change your mind. The smarter you are, the more tools you have at your disposal to reason out complicated methods by which you may be correct. Of course, if your position is untenable enough, even these methods will appear ludicrous from the outside.

You can, therefore, be an excellent doctor and even develop new methods for brain surgery while being simultaneously unwilling to drop absurd beliefs inculcated into you during childhood. Yes, you sound stupid to everyone else, but if you've extended and reinforced these beliefs over your entire lifetime you may be so unwilling to drop them that ridicule isn't enough of a push.