The fbi state that 67% of sex crimes are against children and estimates that only 37% of total sex crimes get reported. Long story short that would mean that 1 in 13 Americans is currently an abused child or was abused as a child. In the digital age that's a lot of photos.

Personally, I grew up in the golden age of Facebook. I cannot accurately measure how many nudes I sent and received over Facebook, Skype, private messages on various platforms, text, email, email to text, flash drive, my highschool gf and I bought a 1TB external back when that was an unreasonable amount of storage, we'd leave nudes for each other when we traded it off to back up music or transfer movies. I can say with absolute certainty that Facebook could make an perfect 3d model of both her and my nude bodies between the ages of 15 and 19 down to the angle of my dick.

Cockroach rule states for every 1 you see there's 10 you don't. If my freshman class was 200 people and I knew at least 20 that had been sexually active, then every single one of them sent nudes. Consider that internet grooming is one of the most common forms of child abuse, and now we see that the amount of naked children photos on the internet is likely equal to if not larger than the amount of photos of adults.

It's why removing child porn from current models is impossible. It's baked in. So instead of scrapping them outright they put a small bot between you and the porn machine that tells you no if you use certain words. This is wholly ineffective and can just be skirted around by using different words that the operators didn't think of.