>Yes, speaking to someone in an attempt to pressure them not to speak to someone else is indeed a form of speech.

No, it isn't merely a form of speech. It's free speech. It's just as free as any other kind of speech. Free speech allows for conflict with speech, and it doesn't guarantee all speech all possible platforms.

You don't get to decide that only the speech you agree with gets to be free, but speech that disagrees with that doesn't.