There's a reason that it's constantly brought up - Twitters content moderators are literally pedophiles, as are Facebook's, as are Reddits. They've figured out how to "self-police" as it were, assuring that enough is deleted and the rest is hidden in PMs and moderated with other tags when caught.

Speaking for personal experience, I met a Facebook person at Folsom Street Fair, through a friend of a friend who I had already marked as super fucking creepy. They were remarkably upfront about it, being drunk and apparently I have a good poker face. See also the "Aimee Challenor" affair at Reddit, and the fact that their initial defense was "Highly recommended by other staff" - They never looked further into that, for a fact.

the argument isn't against freedom of speech, it's against this mythical implementation of free speech in which content moderation is magnitudes better than what is known.