This is an interesting framing; I enjoyed reading it. I would submit the following....
I ran my own dial-up BBS back in the day. I paid for the computer, the software, and the phone line. You're going to seriously sit here and make the argument that I don't have the right to exercise some control over the content users are contributing to the service, when I'm the one who paid for and is maintaining it?
I think the huge difference here is that the BBS was *only* censored by you, and it was less-public than Facebook or Twitter.
The difference between your BBS and what Twitter and Facebook do is that they implement an algorithm to determine what users see. It's not simply an uncurated list of all of the content creators a user subscribes to, it's 'tweaked' and 'optimized' behind the scenes, with no clear ability for users to tweak it manually or pick a different algorithm, and whose parameters are treated with all the transparency of the Coca Cola formula...and like Coca Cola, lots of users do ultimately like the taste, but it's ultimately detrimental to one's long term health.
I've said for years that the solution for Facebook and Twitter is to allow third party algorithms. We've had this for years. I can spin up my own e-mail server and I can either 'raw dog it' and read all of my mail in its spam-laden glory, or I can spin up my own ScrolloutF1 or Xeams server and tweak exactly how I want my mail filtered, or I can use Miracast or Postini or Barracuda or Cisco Ironport and let those companies 'curate' what e-mails I actually see.
If social media companies allowed for third party API access that, in turn, allowed users to pick which algorithm they see. Or, allow users to have a 'raw dog' mode that shows everything with no algorithmic prioritization at all. Yes, Facebook has this, but it needs to be enabled each time...switching this around so that algorithmic curation was the one that needed to be enabled would help the need for neutrality.
None of this was the case in the BBS days, because user lists were small (tens to hundreds, not billions), and there wasn't really a way to curate content other than human readers. With Facebook, Twitter, Reddit, Instagram, and Tiktok having subsumed nearly all of the smaller vBulletin communities that preceded it (and the IRC / BBS / USENET forums that preceded those), the need for a "skip to the good stuff" button is understandable, but to your point regarding social networks not being liable while also being publishers, there's equally a needed middle ground where end users have better leverage over 'the algorithm', so that it balances the need for the website to make a buck (yes, advertisers are going to want some assurance that their ads are going to see more eyeballs) with users' ability to better avoid some of the more problematic implications of a singular, black-box algorithm.