> Freedom of speech is a principle that supports the freedom of an individual or a community to articulate their opinions and ideas without fear of retaliation, censorship, or legal sanction.

Nobody is being censored by the inability of a third party to act as a parallel distribution channel. Nor does freedom of speech have anything to do with entitlement to an audience. No website infringes upon freedom of speech by having a paywall on UGC, as neither the contributors nor readers are worse off than if the site didn't exist.