Reasonable people might disagree, but I think hiding art like this behind NSFW tags is an absolutely ridiculous idea brought about by hypocritical censorship policies in mainstream social media.
Public spaces are full of naked statues. Art pieces like the birth of Venus has been accepted into the public space since forever. And now Instagram is shadow banning museums for posting pictures of traditional art? Who exactly are they trying to protect?
At least personally, when I filter NSFW content, it's to avoid pornography. Not to filter out art that has been accepted in the public space for centuries, if not millennia.
They're trying to protect US "conservatives" who think looking at naked people will somehow harm their children. In reality they're just trying to prop up their inhumane backwards ideology by trying to censor anything that might question it. The disgusting thing is how successful they are with their bullshit.