1) You don't require account to surf the forum.
2) Age restrictions are stupid, just look at porn sites. If site requires kyc to confirm age, it's even more stupid.
3) This thread is stupid.
1) I think he want to let his child to open a new thread if there's a question or something that need to be discussed, not only read other people replies.
2) Accessing porn site isn't that easy, you need to use VPN and there's a warning message if it's only for mature 18+ years old people. In this forum you don't need to use VPN and there's no warning message about age restrictions.
3) I don't think it's stupid, you can find a lot thread asking if teach Bitcoin to the minor is good or not, some users even already teach to their kids which younger than 13 years old boy.