Destruction of art as representative of unacceptable thought.
This has happened many times. French Revolutionaries destroyed cathedrals and art. The Soviets and communist chinese had strict rules governing what sort of art was acceptable. The Nazis on taking power famously burned piles of "degenerate art". The most recent example I can think of is the Taliban in Afghanistan.
Taliban insurgence/occupation Upon the resurgence of Taliban rule from
1996-2001 the ban on most forms of art and cultural expression was
immediately implemented. The Taliban’s war on art was inspired by
the Koran. The Koran forbids the portrayal of living things, whereby
drawing or sculpting living things is recognized as a direct affront
to the Almighty. Among the initial acts of removal were dragging
paintings out of homes, book burnings containing art work, public
execution to TV sets and the discontinuation of music. In 1996, at
the very beginning of the Taliban's rise to power, the entire card
catalog archiving the art at the Afghan National Museum was burned in
order to keep the rebels warm. The systematic destruction of
museums and their collections, to include film archives were purged to
cleanse them of the "unIslamic" depiction of the living and human
In your world, art must celebrate the values of the ruling party. Art which does not do this is degenerate or heretical or treasonous. Persons interested in making such art must do so in secret. It is not farfetched at all.