Seems like they are mishmashing common carrier, the safe harbor provisions of the DMCA, and some magic dust and calling it “liability shield”.

Section 230 of the Communications Decency Act, 18 U.S. Code § 2257 and 47 U.S. Code § 231.

> Section 230 of the Communications Decency Act

This is literally the opposite of what you are claiming. To quote wikipedia,

"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."

> 18 U.S. Code § 2257 ( https://www.law.cornell.edu/uscode/text/18/2257 )

This is the law requiring record keeping for producers of pornographic content. This has nothing to do with what we're discussing here.

> 47 U.S. Code § 231 ( https://www.law.cornell.edu/uscode/text/47/231 )

This law requires people who make porn available to not allow minors to access it. The closest thing I can see that relates to our point is that it grants immunity to ISPs for porn sent over their network.

All three are different laws, yes, but the latter two also make it clear that service providers are immune from liability for third party content in those contexts if they aren't actively participating in its selection or alteration, excepting justified deletions.

You said it's completely false that exercising control over content on one's network diminishes a provider's ability to claim safe harbor. I've given you two laws on the books in the US that say otherwise. What are you basing your claims on?