[nescioquid]

I agree with you in spirit, though I feel like the issue is more about whether social media are common carriers [1] or publishers.

They shield themselves when they claim to be a carriers, yet act like publishers. The monopoly aspect, I agree, would be more important to speech, given they behave as publishers of what you may as well consider on-spec content.

I'd like to get clear on to what degree they should be considered carriers or publishers.

[1] https://en.wikipedia.org/wiki/Common_carrier

[planetree]

They're publishers: they profit from advertising from content, and don't charge a carrier fee. Seems simple enough.