You have to squint to see the output of an LLM to be speech. The input is clearly speech but the government is not preventing anyone from writing or publishing prompts, only from running those prompts through the model.

In the case of the crypto export ban, the government was attempting to suppress the release of cryptographic research. For example, if a cryptographic researcher wrote a paper on a cipher and they included a definition of that cipher in the paper, that was an "export" of cryptography. This is very clearly a restraint on speech that violates the first amendment and after much legal wrangling the government agreed and the issue evaporated.