What was considered “canon” wasn’t monolithic, but was always changing over time even within the first century of the American Republic.
For instance, the teaching of Western Civ in the way we understand it now only started to become popularized after WWI and was considered “Modern” by Oxbridge as late as the 1920s.
Also, while William Shakespeare’s plays are considered highly respectable classics over the last century or so, they weren’t regarded nearly so much back in his day or some years afterwards.
In fact, when Oliver Cromwell’s Puritans won the English Civil War and beheaded Charles I, they actually BANNED and DESTROYED the very theater upon which Shakespeare’s plays were staged along with many others because they felt it was an affront to their religious sensibilities.
Only the restoration of Charles II and the elimination of the Puritan’s political influence brought Shakespeare and his plays from hiding.
The destroyed Globe Theater wasn’t rebuilt until 1997.