Power to the people.
As to "many cases where online communities document or facilitate crimes elsewhere", why criminalise the speech if the action is already criminalised?
That leaves only "Campaigns to harass individuals and groups". Why wouldn't moderation tools as powerful as the ones employed by Twitter's own moderators deal with that?
[1] https://mtsu.edu/first-amendment/article/970/incitement-to-i...
That is, it's not clear in the US you can ban something on the basis of it being immoral, you need to have the justification that it is "documentation of a crime".
This does not stop the FBI from being a major child porn distributor, despite that meaning the FBI is re-abusing thousands of victims under this rubric.
That's what makes it illegal? What if it's done on a private forum that the victim never finds out about? What if the victim is, say, dead? I don't think those change the legality.
It is, in general, really really difficult to pass speech laws in the USA because of that pesky First Amendment -- even if they're documentation of a crime. Famously, Joshua Moon of Kiwi Farms gleefully hosted the footage from the Christchurch shooting even when the actual Kiwis demanded its removal.
But if you can argue that procurement or distribution of the original material perpetuates the original crime, that is, if it constitutes criminal activity beyond speech -- then you can justify criminalizing such procurement or distribution. It's flimsy (and that makes it prone to potentially being overturned by some madlad Supreme Court in the future with zero fucks to give about the social blowbacks), but it does the job.
In other countries it's easy to pass laws banning speech based on its potential for ill social effects. Nazi propaganda and lolicon manga are criminalized in other countries, but still legal in the USA because they're victimless.
If this makes you wonder whether it's time to re-evaluate the First Amendment -- yes. Yes, it is.