Yeah, unfortunately kids having smartphones is very often a case of parental negligence. Just like some parents would buy little Jimmy GTA without even bothering to think about whether that's appropriate, some parents will get their young child a pipe to the worst parts of the Internet without thought.
It's not negligent to allow your kid to be free on the internet nor is it negligent to let them play games not meant for their age group.
It's negligent to let those affect the social behaviour of the kid by themselves. Most kids get lessons by their parents and freedom to do what they want.
