The distinction between "art" and "pornography" is also somewhat artificial. It's hard to argue that [3] was not meant to be prurient when the model (underage, by today's standards) shortly thereafter became a mistress of the King of France, based on him having seen the painting. And some stuff that was painted might get you banned from OnlyFans even today, e.g. [4].
But the problem, it seems to me, is that the internet has turned into a place where (1) everything has to be "safe for children" and (2) said safety standards are defined (through US influence, I strongly suspect) to be highly permissive of violence, but super strict on nudity.
[0] https://artsandculture.google.com/asset/the-war/CwHM2HdTO3l2...
[1] https://www.wikiart.org/en/max-ernst/the-angel-of-the-home-o...
[2] https://www.wikiart.org/en/matthias-grunewald/the-crucifixio...
[3] https://commons.wikimedia.org/wiki/File:François_Boucher_-_B...
[4] https://www.wikiart.org/en/jean-honore-fragonard/girl-with-a...