It doesn't break the liability shield because it's not being selectively enforced.
If YouTube deleted some porn but not others, this protection would no longer apply. Reddit is allowed to delete content that violates their ToS without needing to answer to anybody.
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.
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?
Government/whatever party has to compensate a common carrier a reasonable amount of money for determining and filtering content. Not having tools to do it means a company gets to say "this would cost X, write us a check". If X is too big, government/other party tends to walk away. In my previous life, we have used this argument successfully to quash several court orders. The reason why we were successful is because a very smart attorney that happened to be a relative of a founder convinced him one day that under no circumstances should we develop such tools ahead of time.
One of our competitors had these tools developed. They had a similar court order served on them. They attempted to use the same argument we used. They failed because the government offered court the evidence that those tools already existed and were used by our competitor and hence there was no undue burden.
[Edit: Responding here due to rate limiting]
> It's FUD because it does not apply, at all, to the existing scenario. Common Carriers have specific legal meanings, and internet companies don't fall under that.
This is also unclear. Common carrier is reasonably well defined based on what was known about certain technologies at the time.
NSPs/webhosting providers/CDNs/etc have never litigated their common carrier status to my knowledge as in most of the cases it does not appear that being a common carrier is beneficial to them. This does not, however, mean that there cannot be a situation where being a common carrier would not be advantageous to a NSP/CDN/webhoster. This is why most of them would prefer to behave like common carriers even if they are not - it is optionality and having more options is typically better.
This comes up all the time. During the Obama administration there was talk about reclassifying network services so that this would apply (it would make things like home internet far more competitive if it was). That never happened.
ISPs actually do. And they are very much internet companies.
CF's whole mistake was to pretend that they were nothing more than dumb pipes and that what was legal or at least not explicitly ruled forbidden on a case-by-case basis was good enough for them. They never were dumb pipes, they always had editorial control and they provided the proof of this themselves.
The idea that exercising some control over the content on someone's network or application removed their various liability shields is also completely false. Youtube removes pornography and terror related videos, and sites like reddit remove "abusive" (defined by their TOS, not any law) content, all the time. Never once has this broken their liability shield.