Is it?

I think “you can’t show porn to kids” seems like something well within the authority of a state to make a law about, even if the implementation is hamfisted and ineffective.

My understanding is that porn would be considered obscenity, and obscenity is generally not protected by the first amendment, and can generally be regulated much more strictly.

Do you think the same way about physical media? Like, do you think we should be letting kids buy porn magazines? Or that it should be legal for someone to wait outside a school and hand kids porn as they walk home?