Earlier quoted context omitted.
Should books require an age rating? What about spoken words? What makes online speech different, from the perspective of the Constitution that limits the power of the state?
The difference is one of redressing a concrete dysfunction. Libraries or the local bookstore or whoever aren't trying to sneak into your home, onto your child's school bus, into your child's classroom, while pushing various extremist publications purely for their own profit (ie "engagement"). We do in fact have zoning laws - I can't inadvertently encounter a strip club in a quiet residential area. Meanwhile it's comm…
Mandates on how speech must be structured are a violation of freedom of speech, Constitutionally speaking.
“Redressing a concrete dysfunction” does not appear in the Constitution as an exemption to guaranteed rights, as far as I am aware. The proper remedy for this kind of problem is an Amendment, assuming you can get enough people to agree with your assessment.