Censorship is one party telling everyone else what they can and can't see.
Prohibiting content is censorship -- it's telling people what they can't see.
Prohibiting filtering is also censorship -- it's telling people they have to see your thing in place of the thing they want.
Filtering is inherently a weighing of false positives against false negatives.
If you require filtering then the false negative rate has to be low/zero, so the false positive rate goes through the roof. No Nazis but also no Republicans or Democrats.
If you prohibit filtering then the false positive rate has to be low/zero, so the false negative rate goes through the roof. Everyone is deluged by spam and malware.
Section 230 doesn't apply to copyright and look at the mess that has been -- worst of both worlds. Copyright infringement is still prolific but people use fraudulent copyright takedowns for things they don't own left and right, and the platforms execute them because they have minimal incentive to question anything.
What you really want is the middle ground where platforms have to compete with each other for users, so they can ban things everyone hates (spam) but lose users if they ban things those people are legitimately interested in (e.g. minority political opinions).
The problem isn't Section 230, it's the lack of competition which gives the major platforms too much power when they decide to censor something. It has to be the marketplace of ideas, not the monopoly of ideas.