Hmm. I don’t really disagree with your overall sentiment, but child pornography is universally considered bad because it involves real children being exploited. If it’s completely fictional, well, maybe it should be banned, but it is not the clear cut evil that something involving real children is. It’s like the difference between snuff films and depicting murder in fiction. You should distinguish between the two, actually, even if I see why you’d advocate for it all to be banned.