Cult indoctrination could be explained by this but could also be explained by the fact that a certain number of formerly gifted kids, who have been ostracised during their childhood and have low social skills tend, to gravitate around the rationalist community. I do believe that those people are more likely to be indoctrinated.
From my readings of the Zizian, they also don't seem to easily change their mind, they instead have had a tendency towards very radical opinions that progressively become more extreme.
I argue that having opinions that progressively become more extreme is in fact changing one's mind. That might not be the kind of mind changing we immediately imagine when we think about changing one's mind, but it is mind changing nonetheless.
I'm not trying to be clever; the fact that this flies under the radar just means we might be looking for "changing minds" in one form when it's mostly occurring in another.
People who feel ostracised or underappreciated tend to make good marks for cults and extremist groups in general. Another commenter pointed out that changing an opinion is a more emotional process than we'd like to assume.