If bias works how conservatives think it does, then grown adults are clearly just biased against belief in the Tooth Fairy.

cOLLeGe iS bIaSeD! hOw cOmE tHaR's nOt aLoTtA cOnSeRvAtIvE sOcIoLoGiStS? It's for the same reasons that there aren't many grown adults who believe in the Tooth Fairy. Or evolutionary biologists who are Young Earth Creationists. Or electricians who are Amish. People who don't know much about anything, and have never reconciled their political beliefs to what little they do know