That's what the first amendment says:

"Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances."

This has to do with the government creating laws that curtails your right to free speech.

Freedom of speech isn't a right to a particular platform on which to speak.

Much like OKP, despite the repeated protests of certain people, we don't a right to post or even to membership itself. These things can be revoked without notice, for any reason, or no reason at all, and it still doesn't infringe on our right to free speech.