You like to knit. You joined a knitting forum online. You signed their terms of service, which says only posts about knitting are accepted and all other posts will be unknit.
You knit yourself a scarf. It curls up on the ends and is unwearable. You make a post on your knitting forum asking how to knit a scarf that doesn’t curl. It’s removed. You appeal. The moderators say it doesn’t have anything to do with knitting.
You sue.
Under section 230, the courts tell you that the forum moderators are the sole arbiter of what is knitting on their forum and find against you.
Without section 230, the judge and/or jury review your post and the terms of service and decide for themselves whether one fits under the other. Then they find in your favor or against it as appropriate. Then everyone pays huge legal bills.
It works in reverse. You see a post about how to change a tire on your knitting forum and ask that it be removed. It stays. You sue. Section 230: Forum decides what knitting is on their forum. Otherwise: Judge/jury decide whether the post meets TOS, more legal bills.
Replace “not knitting related” with “hate speech”. Replace your scarf post with “This election is kinda fishy”. Replace the tire changing post with “All cisgender white males need to be guillotined.” Welcome to Facebook, Youtube, Twitter.
Section 230 was not well defined when it passed. It did not have to be this strong, but multiple court cases expanded its power and ascended it into oppressive status, which is why “not knitting related” is protected as “otherwise objectionable” in the wording of the law. I mention this because otherwise it’s not obvious how the law as written has led to today.
https://uscode.house.gov/view.xhtml?req=(title:47%20section:230%20edition:prelim)