What information in these children's books is undermining dictatorial governments? The government isn't censoring e.g. Howard Zinn's A People's History of the United States or Solzhenitsyn's Gulag Archipelago - these are literally just picture books with racist caricatures in them. You have no right to shout "fire" in a crowded theater, and you have no right to denigrate your fellow man.
Of course you do. Can you imagine what the world would be like if the government gave itself the power and created the bureaucratic machinery to stop people denigrating their fellow man? It would be a dystopian nightmare.
I don't see a government censoring this book. Is it illegal to have this book? Should I now force barnes and noble to sell my radical insurrectionist anarchist zines? They are gagging my right to free speech!
There's a difference between "you shouldn't do hate speech" and some sort of 1984/V-for-Vendetta mechanism to ensure that nobody ever does hate speech. Laws and ethics are not the same thing.
The laws in the United States are pretty convoluted, and I don't think they align with human rights all that well, especially given the treatment of imprisoned folks or asylum seekers. However, I do think that causing mass hysteria for kicks (shouting fire...) is wrong and you should not do it.
I'm curious: do you believe that there is anything that one does not have the right to say?
> "You have no right to shout "fire" in a crowded theater"
This is completely false. It's nothing more than a mis-quoted opinion of a justice in a very old case which was eventually overturned and allowed exactly this kind of speech.
Please inform yourself of the laws you're claiming exist before you try to make arguments about them.
In particular, this was an analogy used by Oliver Wendell Holmes in Schenck vs United States. The act which he compared to "shouting fire in a crowded theatre" was passing out leaflets opposing the draft, ie the government's power to force people to go to a war by which the American people were not threatened.