"Sorry I didn’t explain properly- for those defending him, how would you feel if your own son or daughter had been sending photos to him, or if they had been on the receiving end of his threatening messages? Would you be so keen to let it all go?"
I have a 17 year old. If this was them, I don't think having the story all over the internet and being the talking point everywhere would be doing them any good. Especially if they were vulnerable (addict). And more so if they, now at 20 years old, are adamant that there was nothing illegal happening.
Being hounded by tabloid journalists (if the family name gets out there, which I suspect it will at some point) isn't how I would protect my child.
The internet stories will be there forever. Following the young person around forever. Every job interview, every bank account opened (money laundering forms often ask for internet search to be done for any adverse stories) etc.
I'm not saying this isn't sleezy. It is. The whole sorry situation is just a big mess. But for me, potentially exposing my (adult) child's mistakes for the world to see for a long time would give me big pause.