Section 230 explicitly protects their right to block content they consider objectionable (see added highlighting):
47 U.S.C. § 230 (c)
(1) Treatment of publisher or speaker
No provider or user of an interactive computer service shall be treated as the publisher or speaker of any information provided by another information content provider.
(2) Civil liability
No provider or user of an interactive computer service shall be held liable on account of--
(A) any action voluntarily taken in good faith to restrict access to or availability of material that the provider or user considers to be obscene, lewd, lascivious, filthy, excessively violent, harassing, or otherwise objectionable, whether or not such material is constitutionally protected
I don't understand what people think eliminating 230 protection for the techs will buy them.
Do they think that FB will no longer be able to curate what gets posted there?
Publishers typically are much more restrictive in what speech they allow on their platforms than the techs are.
If you force them to act as publishers you'll get much narrower range of opinion like you have today from The Nation or Breitbart.
What people really want is to use someone else's platform to make money for themselves without having to respect the owner's property rights.