one of the worst things to happen to free speech is this conflation of “right to speak” with “right to be heard”

Thank you for this tight summary. As a greybeard, I'll note this conflation was present from very early on, and it was partly responsible for the heat death of Usenet. No amount of logical, prepared rebuttal budges people from the idea that the two things are the same. The conflation might be a human tendency, a cognitive bias that almost everyone has.