Fair to assume that the library of Alexandria contained books written by the most erudite scholars and philosophers of their day, not Joe and Jane and their cohort of terminally online gatekeepers.
Likely some other librarian disagreed with some inclusions and certainly many readers disagreed with the content. They must have had a system for all of this. It was far less open than Wikipedia.
IIRC, they seized all scrolls from all ships in the port, in many languages. They likely had many "errors" according to other librarians and many readers.