As far as I can tell (and I am not a lawyer) you are wrong about this and there is case law to prove it. As wikipedia says:
"The act was passed in part in reaction to the 1995 decision in Stratton Oakmont, Inc. v. Prodigy Services Co.,[3] which suggested that service providers who assumed an editorial role with regard to customer content, thus became publishers, and legally responsible for libel and other torts committed by customers. This act was passed to specifically enhance service providers' ability to delete or otherwise monitor content without themselves becoming publishers. In Zeran v. America Online, Inc., the Court notes that "Congress enacted § 230 to remove the disincentives to self-regulation created by the Stratton Oakmont decision."
And here is the link to the court decision being referenced:
https://w2.eff.org/legal/cases/Stratton_Oakmont_Porush_v_Pro...
> Any small site taking reasonable measures to manage their site would be fine.
The case law indicates the opposite. Without 230, small sites would have to take NO MEASURE to manage other peoples content on their site. As soon as they took any "reasonable measures" to restrict that content they would assume the role of publisher and become liable.
So, no, there is no way removing the blank check we cut big tech is going to hurt small startups or a community forum. And most of those are going to have human moderators that do a much better job than those "automatic filtering tools" you seem to suggest are a solution.
The whole point here is that automatic filtering doesn't work. We've seen YouTube, Facebook, and Twitter prove that. Of course, Google has hundreds of billions of dollars at it's disposal, but it isn't hiring human moderators, because it has no reason to: Our government holds that Google isn't responsible for anything on it's platform, so it is better off keeping the money as profit.
Now, where it starts to get interesting is perverse incentives: Much of advertising profits comes from malware and scams. Ad companies make billions off this illegal, criminal behavior. And since we've granted them platform immunity, because it's "user content", they're free to keep making that money. They have no reason to take down illegal content, they can't be held responsible for cash cow scams like the fake rehab center fiasco that make them millions. (Source: https://www.theverge.com/2017/9/7/16257412/rehabs-near-me-go...) Even if they get pressured to shut them down, they get to keep all of the profits.
Section 230 protects companies which knowingly (and this is key, intent is important) do not remove illegal and criminal conduct because it is profitable, and they can't be held responsible for it. Section 230 does not protect small businesses, and the marketing to protect it relies on fundamental misconceptions about basic legal responsibility. Companies without intent to profit off criminal conduct are protected by the basic concepts of our legal system: That you can't commit a crime without intent.
It's amazing how the organizations promoting how critical Section 230 is to "small businesses" are funded by the five largest companies in the US by market cap. (The Center for Democracy & Technology spoke out against SESTA-FOSTA in some articles today, Amazon, Apple, Facebook, Google, and Microsoft are all top tier sponsors.)