I can understand why UNESCO sets the day as "Book and Copyright" Day. As it says on its website, it is not just reading but also publishing and the protection of intellectual property that it seeks to promote. That is fine in itself, but as someone who so loves reading, I would say the day would be better focused if it were dedicated to celebrating reading alone. Couldn't another day be set for the promotion of copyright?
Journée Mondiale du Livre
UNESCO says on its website that it was "a natural choice" that today is chosen as the World Book and Copyright Day, as 23 April is a symbolic date for world literature, because "on this date and in the same year of 1616, Cervantes, Shakespeare and Inca Garcilaso de la Vega all died", and it is the date of birth or death of some other prominent authors.