If Making of a Gadol is “completely unreliable,” why ban it? That would be kind of like telling your child not to read a book that says the sky is made of cotton candy – it would be so absurd that there would be no reason to ban it, and banning it would just give the absurdity some legitimacy.
Perhaps the “gedolim” banned the book because it is reliable but presents a perspective on talmidei chachamim that they would prefer we not see. Ah, back to the begining – the parent of all klal yisrael doing us a great tova by protecting our fragile minds and hearts from improper influences by restricting our access to certain books. No wonder some would seek to ban our children from libraries.