A Matter of Definition
A cultist is someone who clings to a false belief out of loyalty to his cult, regardless of evidence. He believes what he is told to believe because he trusts and loves the witchdoctor or false prophet allegedly speaking a truth rejected by the world, a special truth, a personal truth.
A cultist takes pride in being deaf to reason.
The sad thing is, that there are legitimate times and places when an honest man should not listen to reason, such as when Nazi spies are trying to give you reasons for betraying your flag, or when a seductress is trying to give you reasons for betraying your wife. The cultist puts his falsehoods of his cult on the same high pedestal where an honest man puts his faith.