the discussion was about works that were declared illegal. The burning of the library of Alexandria under Theophilus has some connection to that idea, but it is I think wider. Every referenced lost work from Rome was not lost because they were declared illegal.
The discussion was ‘history is written by the victors’, which isn’t just making books illegal. It also includes making things (intentionally) irrelevant, destroying old copies, etc.
Hell, most early Bibles count, or do you think the council of Nicea resulted in something other than what is being described for large swathes of early church writings?