My understanding was that Section 230 was to protect platforms from liability. It was not to create new restrictions on how they must or must not otherwise regulate & shape speech on their platform.

This implication that platforms have to allow anyone to say whatever they want unless it's a certain pre-set class of illegal speech, lest they become some other service class with additional liabilities for speech, seems facetiously misguided & contrary to all evidence there is for how Section 230 was proposed, discussed, and how it describes itself.