No small few religious believers talk about their "doubt". They're not fanatics like those weirdos; they're not 100% certain of their beliefs; they admit they could be wrong.
Are these protestations meaningful? If so, in what sense?
A skeptic, such as myself, means something very specific about not being sure about some matter of truth: There are logically possible experimental results or other observations that, if they contradicted the theory, would entail modifying the theory. If a better, simpler theory were proffered, I would abandon the old theory altogether. If I drop a rock and it doesn't fall, something is wrong with the theory of gravity.
If religious belief means belief in some sort of religious truth, then what could change your mind? If you're convinced that your religion is true, then you believe that it's true regardless of your opinion; changing your opinions shouldn't change your conviction of truth.
Contrawise, if you could just arbitrarily change your mind about your religion, then your religion is a matter of your personal opinion and preference. In which case, by what virtue do you dignify your personal preferences with the name of "religion"?
Saying you might be mistaken is pure bullshit if there's nothing that could actually convince you that you were mistaken. And if you could just arbitrarily change your mind, you don't have a religion at all.