" it's the job of any state to regulate actions that cause serious harm to people."

Shooting someone is already a crime and always has been.

Posessing a magazine with more than 7 rounds is not an action at all, and does not harm anyone.

The reason the parent used the word "nanny state" is because he's describing laws that prohibit things for which there is no victim.

Possessing a magazine does not cause harm to anyone. There are already laws against causing harm to people.