As someone who operated on the "adult internet" with payment processors and related infrastructure without being 18, I still carry forward the constant fear that I'll be banned for retroactive Terms of Service violations incurred when I was a kid. It really sucks when it's services like AdSense because you're just screwed forever. I really really wish the internet was more supportive of "early hackers" who want to ex…
For other services there is enough bureaucracy that it's easier to avoid by not providing the service to minors.
It's also easier to ban accounts for life when they lie about who they are. You don't run the risk of aiding fraud and being fined if you make a mistake, because you banned them.
There was nothing preventing the kid from creatibg content. It was in using Ad Sense to make money off it.