> Parents just want to be able to designate a device as belonging to a child---one setting---and have that respected.

The problem here is, what does that actually do?

If you say the device is for kids, can the kids then see content related to firearms? What if the parents are Republicans and don't want that censored for their kids? Also, what does it even mean? Does a YouTube video on firearm safety get blocked because it contains firearms? Should "kids" be able to view sex education content?

If nobody agrees what should be blocked then the reason they don't have a setting is that nobody knows how to implement it.