Why am I being forced to prove to my OS that I am an adult just because of your inadequate parenting skills?
Isn't the OS thing specifically California state law? If so, the answer is "California is unfortunately very influential": https://en.wikipedia.org/wiki/California_effect
(And I'm saying this as someone who doesn't live in the US, nor care to).
Wait what? How did we go from "Users of social media need to be at least 16" to "Users of OSes need to prove they are adults"?
Because lots of people have inadequate parenting skills (last time I checked you didn't need a license for parenting) and tech companies are actively exploiting that.