The biggest issue with this line of thinking is, how do you prove it's CP without a victim. I suppose at a certain threshold it becomes obvious, but that can be a very blurry line (there was a famous case where a porn star had to be flown to a court case to prove the video wasn't CP, but can't find the link right now).
So your left with a crime that was committed with no victim and no proof, which can be really easy to abuse.
Edit: This is the case I was thinking of - https://nypost.com/2010/04/24/a-trial-star-is-porn/