Controversial opinion:
It's fine for social media servers to delete posts or censure users who post art that, while not technically illegal, appears to depict sexualized children, or sexualized characters who appear underage (even if they are supposedly a 5,000 year old dragon or sentient anthropomorphic car or some shit).
Likewise, it's 100% fine for servers to nuke posts that seem e.g. racist, even if the author intends them to be some kind of galaxy-brain-level parody.