Say you were a guardian or parent and get to decide when a child can get a phone or use a computer and get internet with it. If you wish you can also install software and change router settings to what you see fit.
Some parents decide to forbid the internet completely, others are more relaxed. Some go the helicopter route, and some do not care whatsoever what their kid does online.
What is your policy on letting a child use the internet?
Wanting to protect your kids and struggling with “sheltering vs free reign” type decisions is most of the job of parenting. Whether that is Internet or crossing the street or whatever. Parents who end up overprotective don’t always start from a bad place and parents who end up excessively permissive don’t always start from a good place. Most people just out there trying to do their best in the face of uncertainty.