No, even then it still isn't. A device should not protect you from making bad decisions. It should be an aid in making good choices, not a nanny keeping you safe because you can't be trusted to do better.

So, turn off your firewall if you don't want to be protected.

Do modern OSes have services listening on external IPs without explicitly told to still?

I think to the parents point, everything should be wide open, all the features possible, and let him configure. By not listening, isn't that 'over-simplifying', let the user decide.