Richard, you like to have documentation and all of that to pick apart and dissect. So, I will provide you with some material that will enlighten you to the reality of what "child pornography" actually is and how it is viewed by a global law enforcement agency - Interpol.
Look around in this website. Take your time. There is lots to go through:
https://www.interpol.int/Crime-areas/Crimes-against-children/Crimes-against-children
You will note that Interpol uses the term "child abuse material" instead of "child pornography" (from the Online Q&A - click on link right of screen for downloading pdf):
1. WHAT DO YOU MEAN BY ‘CHILD ABUSE MATERIAL’?
Child abuse material (CAM) is the term used to refer to the photos or videos taken by an offender, documenting the sexual abuse of a child.
2. IS ‘CAM’ THE SAME AS ‘CHILD PORN’?
The media often use the term ‘child pornography’. This is not appropriate when describing images of sexual abuse of children. A sexual image of a child is ‘abuse’ or ‘exploitation’ and should never be described as ‘pornography’.
Pornography is a term used for adults engaging in consensual sexual acts distributed (mostly) legally to the general public for their sexual pleasure. Child abuse images are not. They involve children who cannot and would not consent and who are victims of a crime.
According to Interpol, child pornography is "child sex abuse material". Someone should tell the WT that.