Increasingly that kind of requirement puts you in the same camp as oppressive nation states. Being a network operator and wanting to MitM your DNS makes you a political actor. Devices you paid for, but don't actually own, will end-run your efforts by using their own hard-coded DNS servers. (See https://pc.nanog.org/static/published/meetings/NANOG77/2033/...)
Though I fully understand I'm in the same camp as oppressive nation states. But until my kids get older I'm in charge, I need to set them up for success in life, which is a complex balance of letting them have freedom without allowing them to make too many bad decisions. Not getting their homework done because they are watching videos is on bad decisions I'm trying to prevent.
So really instead of thinking about this like "parents are acting like nation states" I think it's much better to think of it like "parents are countering corporate nation states."