Showing adult content to minors is also probably not an insignificant part of their business (certaintly a major part if the classification of social media as adult becomes more widespread), and having age be an os-user property might give children more opportunity to subvert the verification. And if enough applications end up behind the maturity wall, they can count on children to badger their parents into setting their account to adult, and the industry will absolve itself of all responsibility once more.

>> They could stop adult content from being shown to minors; it would just take effort on their part to do so

If you voluntarily sensor content, you might be in danger of being held responsible for various things since you control what people see. Phone companies in the US are "common carriers" which means they just connect people, but are not responsible for what people do over the phone (plotting crime or whatever). Social Media is still trying to have it both ways - censor some stuff but not be responsible for anything. IMHO that will eventually fail.

I'm really quite confident I don't want these companies collecting face and ID scans to prove age, so no I think this being an OS problem is actually a very reasonable solution.

because stock price must go up