Certainly you can gainsay that, as you do. So if that's what you mean by it can be debated, point taken.
But I'd agree with the author that it can't be debated - if you are referring to a free society. Unless we adopt an Orwellian New speak version of the word free.
I am all in for legalizing drugs, but don't pretend that all weapon trade, offering hacking services or other nasty stuff needs to be protected in a free society. Freedom of speech is about inconvenient opinions, not about "everything you can do by communicating with others".
The possibility that any speech may slide into commerce would mean any speech is open to observation.
Too high a price IMHO
If the answer is anyone but the people engaging in the speech, isn't that a little dangerous?