"We" as adults at least have the mostly-capable ability to discern good from bad, whereas a child until the age of 14-18 (depending on the topic at hand) does not have the sense of responsibility, especially about the crucial aspect which is his/her own health. Therefore you could expect an adult to be able to take care of him/her-self after the ~age of adulthood, whereas a children is very rarely expected to do so, because most of the times they're not even fully aware of it (consciously speaking, not talking about almost instinctive reactions).

> "We" as adults at least have the mostly-capable ability to discern good from bad

Do we?

Suicide rate among adults in all age ranges is way higher than in teens and pre-teens.

Anecdotally, there are plenty of day to day examples of adults not having their crap together. The historical state of the world is one of them.

> Therefore you could expect an adult to be able to take care of him/her-self after the ~age of adulthood

I used to believe that as a kid... then i became an adult and met other adults who do not remotely have their shit together.

> "We" as adults at least have the mostly-capable ability to discern good from bad

You’re going to be shocked when you find out what Facebook did to the Boomer generation.