Here's a thought: instead of fighting this, make it a requirement to publish the prompts before making a speech. Speeches by politicians being low in information density is nothing new, and the usage of LLMs will undoubtedly make that worse, but it also means that they had to have written a terse description of the information they want to convey. If that were public, people could just read that and not waste time listening to speeches.
It would be ironic if the first use-case for LLMs that creates positive value for society involves ignoring its output, though.