If they can be swayed, then they are conflicted, enough to examine their idividualism counter to the group belief.
This conflict, especially if both sides tugging are strong, could cause considerable distress, but, I think, is a healthy departure, and may lead to resolution of conflict, hopefully, by forming the conclusion, that delusions are ways to insulate self from the harsh realities of life--a way to control panic and fear, etc..
Before a child's forebrain is more fully grown, (and not, fully, grown 'til 30!) belief in fantasy figures is not delusion, because the logic needed to disprove the existence of say, the easter bunny, is simply not there, in most cases--save mega-genius kids: within, their, age dependent group of brain development, they are the front runners by sometimes several years.
An adult's need to be self protecting with a ridiculous belief is child like--why much reference in the Bible are to things childlike, I think, often implying the erroneous assumption that small children are 'pure,' because their helplessness makes them dependent on a bigger, stronger, wiser, whatever, to survive.
Of course, there are just boodles of contradictions in the Bible, reason enough for any rational person to disbelieve, or at least question, the whole thing anyway! i.e, (paraphrased, badly) "when I was a child, I thought as a child, but now I am a man, etc.." vs. "you have to have the purity of childhood to enter the kingdom of heaven."
People with weak identities are susceptible to this hoo-haw, and, or, are very often roped in to it all as a condition of marriage or familial connection.
So, yes, many don't really believe the crazy stuff, but still think that churches, over-all, are 'good' places, with 'good' people. This last, is evidence of false belief, not delusion, per se, since there are, some, good things done by churches and there are, some, 'good' people who are involved in churches, although no more than there are non-church groups doing good, or 'good' people, in the general population.
Personally, I think that Jesus, himself, was not delusional, but mislead by popular misconceptions of the day, and, was a real smart ass. You cannot definitively figure out when he was being figurative or literal from what was recorded on what he actually said. So when interpretations of his, supposed, words, turned in to doctrine, along, and along, it was just one more removal from whatever truth was there, originally, a la the 'telephone game.'