The museum has not, in fact, made any indication that it would wish to cancel (to decide not to conduct or perform) its Charles Dickens exhibition. The sense of 'cancel' being used here is the dumb one.
"Every record has been destroyed or falsified, every book rewritten, every picture has been repainted, every statue and street building has been renamed, every date has been altered. And the process is continuing day by day and minute by minute. History has stopped. Nothing exists except an endless present in which the Party is always right" (George Orwell, "1984")
Outlawing something often gives it extreme power to those that support it - Nazi symbols and concepts appear to gain strength from their pariah status (especially since they signal group affiliation). Aside: pariah is sure to be disallowed soon).