I believe you need to be taught that if you're under-developed you literally cannot be taught it yet.

(Alas I guess that might be true for this lesson too!)

How many cultures on the planet would not find "a photorealistic depiction of a specific teenager getting gangbanged" to be embarassing to said teenager?

Hopefully ALL of them when it becomes possible to effortlessly create fake images like this. It is the only reasonable long term reaction.

Kids already die from extended verbal abuse.

Why would we assume your scenario will occur with even more effective bullying if it isn't already with that?

how do you teach someone whose brain is still developing?

"hey kids, get used to being exploited sexually, as it would be too expensive to require massive multinational corporations to bother to regulate AI"

Teaching someone when their brain is still developing is the BEST TIME to teach them.

Open models cannot be regulated. The genie is out of the bottle permanently.