You can send one message and it'll be received by many.
Facebook may not have to take responsibility for users' content or wrangling with issues such as free speech but they must take responsibility for what and how they choose to amplify and recommend that content to others.
Traditionally this is a power that has only been held by broadcasters. Broadcasters have things like time delays and "dump switches" when they are conducting live shows. The time delays are mostly used to insert the "bleeps" for bad language. The "dump switch" is a more brutal approach that allows them to avoid broadcasting something that is going terribly wrong.
Broadcasters also have "watersheds" that place time constraints on when certain types of things can be broadcast and broadly define who the expected audiences are.
In this case, Facebook are acting more like a broadcaster than a publisher or message conveyer. Because the audience can be more tightly controlled than a regular broadcaster, there is a case to be made for making the responsibility bar higher, not lower, so that inappropriate content cannot be deliberately targeted at vulnerable people.
Then maybe it shouldn't behave like one. FB actively selects articles to show on your feed - via algorithm, instead via human, but the effect is the same.
That is a choice they could easily undo. It is also a choice a large number of people would be happy to see. ("I just want my feed ordered by date, no filtering" is a very common request). The only reason that doesn't happen is that the enragement metrics go up if you select what you present to people.
So FB is deliberately choosing articles to show you, and it is making that selection for monetary gain. How is that not a publisher?
Mailing death threats is illegal: https://www.law.cornell.edu/uscode/text/18/876 (so much for "free speech", eh?)
It doesn't appear to be illegal to post them on Facebook?
The question is: who should be enforcing the law....
If people were regularly mass mailing death threats to large fractions of the population, it would sure as hell get regulated.
I agree that it couldn't work in the way it currently does, but that's what I'm getting at - that maybe it shouldn't be able to work in the way that it does presently. I think that it is much more like a broadcaster than a 'platform', but I know not everyone agrees with that.
That's not quite true. No one blames the US postal service for death threats sent in the mail. Facebook is not the USPS, but it's not a traditional publisher either — and just like the USPS it simply couldn't work if you wanted the same level of editorial oversight as a publisher.
edit: typo